Anthracene derivative, light-emitting element, light-emitting device, and electronic appliance

ABSTRACT

Novel anthracene derivatives are provided. Further, a light-emitting element, a light-emitting device, and an electronic appliance each using the novel anthracene derivative are provided. Anthracene derivatives represented by general formulae (G11) and (G21) are provided. The anthracene derivatives represented by the general formulae (G11) and (G21) each emit blue light with high color purity and have a carrier-transporting property. Therefore, each of the anthracene derivatives represented by the general formulae (G11) and (G21) is suitable for use in a light-emitting element, a light-emitting device, and an electronic appliance.

TECHNICAL FIELD

The present invention relates to an anthracene derivative, and alight-emitting element, a light-emitting device, and an electronicappliance each using the anthracene derivative.

BACKGROUND ART

Organic compounds can take various structures compared with inorganiccompounds, and can be used to synthesize a material having a variety offunctions with appropriate molecular design. Because of these types ofadvantages, attention has been focused on photo electronics andelectronics in which functional organic compounds are used in recentyears.

For example, as examples of electronic devices in which organiccompounds are used as functional organic materials, there are solarcells, light-emitting elements, organic transistors, and the like. Thesedevices use the electrical properties and optical properties of organiccompounds. Among them, in particular, tremendous progress has been madein light-emitting elements.

It is said that the light emission mechanism of a light-emitting elementis as follows: by application of a voltage between a pair of electrodeswith a light-emitting layer interposed therebetween, electrons injectedfrom a cathode and holes injected from an anode recombine in theluminescence center of the light-emitting layer to form excitons inmolecules, and when the excitons in molecules relax to a ground state,energy is released to emit light. A singlet excited state and a tripletexcited state are known as excited states, and it is thought that lightemission can be obtained through either of the excited states.

In an attempt to improve the properties of such a light-emittingelement, there are many problems depending on a material. In order tosolve these problems, improvement of an element structure, developmentof a material, etc. have been carried out.

For example, in Patent Document 1, an anthracene derivative that emitsgreen light is disclosed. However, in Patent Document 1, only the PLspectrum of the anthracene derivative is disclosed, and the propertiesof a light-emitting element to which the anthracene derivative isapplied are not disclosed.

Further, in Patent Document 2, a light-emitting element using ananthracene derivative for a charge-transporting layer is disclosed.However, in Patent Document 2, there is no description of the lifetimeof the light-emitting element.

In view of commercialization, an increase in lifetime is an importantobject, and development of a light-emitting element having betterproperties is desired.

[Patent Document 1]

United States Patent Application Laid-Open No. 2005-0260442

[Patent Document 2]

Japanese Published Patent Application No. 2004-91334

DISCLOSURE OF INVENTION

In view of the above, according to an embodiment of the presentinvention, novel anthracene derivatives are provided.

Further, according to an embodiment of the present invention, alight-emitting element, a light-emitting device, and an electronicappliance each using any of the novel anthracene derivatives areprovided.

An embodiment of the present invention is an anthracene derivativerepresented by a general formula (G11).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,Ar⁴ represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar⁵ represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms, and a direct bond between Ar³ and Ar⁴,between Ar³ and Ar⁵, or between Ar⁴ and Ar⁵ forms a five-membered ringto form a carbazole skeleton.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G12-1).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar⁴ represents asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, andR¹¹ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G12-2).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,and R²¹ and R²² independently represent hydrogen, an alkyl group having1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having6 to 13 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G13-1).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹² to R¹⁶independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 10carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G13-2).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms, and R²³ to R²⁶ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstitutedphenyl group.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G14-1).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹¹ representshydrogen, an 5 alkyl group having 1 to 4 carbon atoms, or a substitutedor unsubstituted aryl group having 6 to 13 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G14-2).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R²¹ and R²²independently represent hydrogen, an allyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G15-1).

In the formula, R¹¹ represents hydrogen, an alkyl group having 1 to 4carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms, and R³¹ to R⁴⁰ independently represent hydrogen, analkyl group having 1 to 4 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 10 carbon atoms, halogen, or a haloalkyl grouphaving 1 to 4 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G15-2).

In the formula, R²¹ and R²² independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, and R³¹ to R⁴⁰ independentlyrepresent hydrogen, an alkyl group having 1 to 4 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 10 carbon atoms,halogen, or a haloalkyl group having 1 to 4 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G21).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,Ar⁴ represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar⁵ represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms, and a direct bond between Ar³ and Ar⁴,between Ar³ and Ar⁵, or between Ar⁴ and Ar⁵ forms a five-membered ringto form a carbazole skeleton.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G22-1).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar⁴ represents asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, andR¹¹ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G22-2).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,and R²¹ and R²² independently represent hydrogen, an alkyl group having1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having6 to 13 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G23-1).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹² to R¹⁶independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 10carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G23-2).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms, and R²³ to R²⁶ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstitutedphenyl group.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G24-1).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G24-2).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G25-1).

In the formula, R¹¹ represents hydrogen, an alkyl group having 1 to 4carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms, and R³¹ to R⁴⁰ independently represent hydrogen, analkyl group having 1 to 4 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 10 carbon atoms, halogen, or a haloalkyl grouphaving 1 to 4 carbon atoms.

Further, an embodiment of the present invention is an anthracenederivative represented by a general formula (G25-2).

In the formula, R²¹ and R²² independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, and R³¹ to R⁴⁰ independentlyrepresent hydrogen, an alkyl group having 1 to 4 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 10 carbon atoms,halogen, or a haloalkyl group having 1 to 4 carbon atoms.

For easy synthesis, Ar¹ and Ar² in each above structure are preferablysubstituents each having the same structure.

Further, an embodiment of the present invention is an anthracenederivative represented by a structural formula (101).

Furthermore, an embodiment of the present invention is an anthracenederivative represented by a structural formula (201).

Moreover, an embodiment of the present invention is a light-emittingelement using any of the above anthracene derivatives. In specific, thelight-emitting element includes any of the above anthracene derivativesbetween a pair of electrodes.

Further, an embodiment of the present invention is a light-emittingelement having a light-emitting layer between a pair of electrodes. Thelight-emitting layer includes any of the above anthracene derivatives.In particular, the anthracene derivative is preferably used as alight-emitting substance. That is, a structure is preferably employed inwhich the anthracene derivative emits light.

Furthermore, in a light-emitting device of the present invention, alight-emitting element that includes, between a pair of electrodes, anEL layer including any of the above anthracene derivatives and a controlcircuit configured to control light emission from the light-emittingelement are included. Note that the category of a light-emitting devicein this specification includes an image display device and a lightsource (e.g., a lighting apparatus). In addition, the following are allincluded in the category of a light-emitting device: a module in which aconnector, for example, a flexible printed circuit (FPC), a tapeautomated bonding (TAB) tape, or a tape carrier package (TCP) isattached to a panel, a module provided with a printed wiring board atthe end of a TAB tape or a TCP, and a module in which an integratedcircuit (IC) is directly mounted to a light-emitting element by a chipon glass (COG) method.

Further, an electronic appliance using a light-emitting element of thepresent invention in a display portion is also included in the scope ofthe present invention. Accordingly, an electronic appliance of thepresent invention includes a display portion. The display portionincludes a light-emitting element as described above and a controlcircuit configured to control light emission from the light-emittingelement.

The anthracene derivatives of the present invention each emit blue lightwith high color purity and further have a carrier-transporting property.Therefore, any of the anthracene derivatives of the present invention issuitable for use in a light-emitting element, a light-emitting device,and an electronic appliance.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B each illustrate a light-emitting element according to anembodiment of the present invention.

FIG. 2 illustrates a light-emitting element according to an embodimentof the present invention.

FIG. 3 illustrates a light-emitting element according to an embodimentof the present invention.

FIGS. 4A and 4B illustrate a light-emitting device according to anembodiment of the present invention.

FIGS. 5A and 5B illustrate a light-emitting device according to anembodiment of the present invention.

FIGS. 6A to 6D illustrate electronic appliances according to anembodiment of the present invention.

FIG. 7 illustrates an electronic appliance according to an embodiment ofthe present invention.

FIG. 8 illustrates an electronic appliance according to an embodiment ofthe present invention.

FIG. 9 illustrates an electronic appliance according to an embodiment ofthe present invention.

FIG. 10 illustrates a lighting apparatus according to an embodiment ofthe present invention.

FIG. 11 illustrates a lighting apparatus according to an embodiment ofthe present invention.

FIGS. 12A to 12C illustrate an electronic appliance according to anembodiment of the present invention.

FIGS. 13A and 13B show ¹H NMR charts of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIG. 14 shows an absorption spectrum of a toluene solution of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIG. 15 shows an emission spectrum of the toluene solution of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIG. 16 shows an absorption spectrum of a thin film of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIG. 17 shows an emission spectrum of the thin film of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIG. 18 shows the results of CV measurement of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIG. 19 shows the results of CV measurement of3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation:2PCzPA).

FIGS. 20A and 20B show ¹H NMR charts of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 21 shows an absorption spectrum of a toluene solution of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 22 shows an emission spectrum of the toluene solution of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 23 shows an absorption spectrum of a thin film of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 24 shows an emission spectrum of the thin film of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 25 shows the results of CV measurement of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 26 shows the results of CV measurement of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA).

FIG. 27 illustrates a light-emitting element of Examples.

FIG. 28 shows the current density vs. luminance characteristics oflight-emitting elements fabricated in Example 3.

FIG. 29 shows the voltage vs. luminance characteristics of thelight-emitting elements fabricated in Example 3.

FIG. 30 shows the luminance vs. current efficiency characteristics ofthe light-emitting elements fabricated in Example 3.

FIG. 31 shows the voltage vs. current characteristics of thelight-emitting elements fabricated in Example 3.

FIG. 32 shows emission spectra of the light-emitting elements fabricatedin Example 3.

FIG. 33 shows the current density vs. luminance characteristics oflight-emitting elements fabricated in Example 4.

FIG. 34 shows the voltage vs. luminance characteristics of thelight-emitting elements fabricated in Example 4.

FIG. 35 shows the luminance vs. current efficiency characteristics ofthe light-emitting elements fabricated in Example 4.

FIG. 36 shows the voltage vs. current characteristics of thelight-emitting elements fabricated in Example 4.

FIG. 37 shows emission spectra of the light-emitting elements fabricatedin Example 4.

FIG. 38 shows a change in luminance with respect to driving time of thelight-emitting elements fabricated in Example 4.

FIG. 39 shows the current density vs. luminance characteristics oflight-emitting elements fabricated in Example 5.

FIG. 40 shows the voltage vs. luminance characteristics of thelight-emitting elements fabricated in Example 5.

FIG. 41 shows the luminance vs. current efficiency characteristics ofthe light-emitting elements fabricated in Example 5.

FIG. 42 shows the voltage vs. current characteristics of thelight-emitting elements fabricated in Example 5.

FIG. 43 shows emission spectra of the light-emitting elements fabricatedin Example 5.

FIG. 44 shows a change in luminance with respect to driving time of thelight-emitting elements fabricated in Example 5.

FIG. 45 illustrates a light-emitting element of Examples.

FIG. 46 shows the current density vs. luminance characteristics oflight-emitting elements fabricated in Example 6.

FIG. 47 shows the voltage vs. luminance characteristics of thelight-emitting elements fabricated in Example 6.

FIG. 48 shows the luminance vs. current efficiency characteristics ofthe light-emitting elements fabricated in Example 6.

FIG. 49 shows the voltage vs. current characteristics of thelight-emitting elements fabricated in Example 6.

FIG. 50 shows emission spectra of the light-emitting elements fabricatedin Example 6.

FIG. 51 shows a change in luminance with respect to driving time of thelight-emitting elements fabricated in Example 6

FIGS. 52A and 52B show ¹H NMR charts of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

FIG. 53 shows an absorption spectrum of a toluene solution of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

FIG. 54 shows an emission spectrum of the toluene solution of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

FIG. 55 shows an absorption spectrum of a thin film of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

FIG. 56 shows an emission spectrum of the thin film of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

FIG. 57 shows the results of CV measurement of 9-{ 4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole (abbreviation:2CzPBPhA).

FIG. 58 shows the results of CV measurement of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. Note that thepresent invention is not limited to the description below, and it isreadily understood by those skilled in the art that a variety of changesand modifications can be made without departing from the spirit andscope of the present invention. Therefore, the present invention shouldnot be interpreted as being limited to the content of the embodimentsdescribed below.

Embodiment 1

In Embodiment 1, the anthracene derivatives of the present inventionwill be described.

An embodiment of the present invention is the anthracene derivativerepresented by the general formula (G11).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,Ar⁴ represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar⁵ represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms, and a direct bond between Ar³ and Ar⁴,between Ar³ and Ar⁵, or between Ar⁴ and Ar⁵ forms a five-membered ringto form a carbazole skeleton.

As the anthracene derivative represented by the general formula (G11),specifically, there are anthracene derivative represented by generalformulae (G11-1) to (G11-3).

In the general formula (G11-1), Ar¹ and Ar² independently represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, Ar³has a benzene ring, Ar⁴ has a benzene ring, a direct bond between Ar³and Ar⁴ forms a five-membered ring to form a carbazole skeleton, and Ar⁵represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

In the general formula (G11-2), Ar¹ and Ar² independently represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, Ar³represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar⁴ has a benzene ring, Ar⁵ has a benzene ring, and adirect bond between Ar⁴ and Ar⁵ forms a five-membered ring to form acarbazole skeleton.

In the general formula (G11-3), Ar¹ and Ar² independently represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, Ar⁴represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar³ has a benzene ring, Ar⁵ has a benzene ring, and adirect bond between Ar³ and Ar⁵ forms a five-membered ring to form acarbazole skeleton.

Another embodiment of the present invention is the anthracene derivativerepresented by the general formula (G21).

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,Ar⁴ represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar⁵ represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms, and a direct bond between Ar³ and Ar⁴,between Ar³ and Ar⁵, or between Ar⁴ and Ar⁵ forms a five-membered ringto form a carbazole skeleton.

As the anthracene derivative represented by the general formula (G21),specifically, there are anthracene derivative represented by generalformulae (G21-1) to (G21-3).

In the general formula (G21-1), Ar¹ and Ar² independently represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, Ar³has a benzene ring, Ar⁴ has a benzene ring, a direct bond between Ar³and Ar⁴ forms a five-membered ring to form a carbazole skeleton, and Ar⁵represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

In the general formula (G21-2), Ar¹ and Ar² independently represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, Ar³has a benzene ring, Ar⁴ has a benzene ring, a direct bond between Ar⁴and Ar⁵ forms a five-membered ring to form a carbazole skeleton, and Ar⁵represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

In the general formula (G21-3), Ar¹ and Ar² independently represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, andAr⁴ represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar³ has a benzene ring, Ar⁵ has a benzene ring, and adirect bond between Ar³ and Ar⁵ forms a five-membered ring to form acarbazole skeleton.

Note that the carbon atoms of the aryl group or of the arylene groupwhich is described in this specification refer to carbon atoms forming aring of the main skeleton, not to carbon atoms of a substituent bondedto the ring of the main skeleton. As examples of a substituent bonded tothe aryl group or to the arylene group, there are an alkyl group having1 to 4 carbon atoms and an aryl group having 6 to 13 carbon atoms;specifically, a methyl group, an ethyl group, a propyl group, a butylgroup, a phenyl group, a naphthyl group, a fluorenyl group, and thelike. Further, the aryl group or the arylene group may have one or moresubstituents. If the aryl group or the arylene group has twosubstituents, the substituents may be bonded to each other to form aring. For example, if the aryl group is a fluorenyl group, the carbonatom at the 9-position may have two phenyl groups, and the two phenylgroups may be bonded to each other to form a spiro ring structure.

In the general formulae (G11) and (G21), aryl groups each having 6 to 13carbon atoms may independently have a substituent. If aryl groups eachhaving 6 to 13 carbon atoms independently have a plurality ofsubstituents, the substituents may be bonded to form a ring. Further, ifa carbon atom has two substituents, the substituents may be bonded toeach other to form a spiro ring. For example, there are substituentsrepresented by the structural formulae (11-1) to (11-16).

Moreover, in the general formulae (G11) and (G21), an arylene groupshaving 6 to 13 carbon atoms may independently have a substituent. Ifarylene group having 6 to 13 carbon atoms has a plurality ofsubstituents, the substituents may be bonded to form a ring. Further, ifa carbon atom has two substituents, the substituents may be bonded toeach other to form a Spiro ring. For example, there are substituentsrepresented by the structural formulae (12-1) to (12-9).

The anthracene derivative represented by the general formula (G11) ispreferably an anthracene derivative represented by the general formula(G12-1) or (G12-2), for easy synthesis and purification.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar⁴ represents asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, andR¹¹ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,and R²¹ and R²² independently represent hydrogen, an alkyl group having1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having6 to 13 carbon atoms.

Also, the anthracene derivative represented by the general formula (G21)is preferably the anthracene derivative represented by the generalformula (G22-1) or (G22-2), for easy synthesis and purification.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar⁴ represents asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, andR¹¹ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,and R²¹ and R²² independently represent hydrogen, an alkyl group having1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having6 to 13 carbon atoms.

Further, in the anthracene derivative represented by the general formula(G11), it is preferable that Ar³ be a substituted or unsubstitutedbenzene ring, Ar⁴ be a substituted or unsubstituted benzene ring, andAr⁵ be a substituted or unsubstituted benzene ring, for easy synthesisand purification. That is, the anthracene derivative represented by thegeneral formula (G13-1) or (G13-2) is preferable.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹² to R¹⁶independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 10carbon atoms.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms, and R²³ to R²⁶ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstitutedphenyl group.

Also in the anthracene derivative represented by the general formula(G21), it is preferable that Ar³ be a substituted or unsubstitutedbenzene ring, Ar⁴ be a substituted or unsubstituted benzene ring, andAr⁵ be a substituted or unsubstituted benzene ring, for easy synthesisand purification. That is, an anthracene derivative represented by thegeneral formula (G23-1) or (G23-2) is preferable.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹² to R¹⁶independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 10carbon atoms.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms, and R²³ to R²⁶ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstitutedphenyl group.

As the substituted or unsubstituted aryl groups each having 6 to 10carbon atoms in the general formulae (G13-1), (G13-2), (G23-1), and(G23-2), there are substituents represented by structural formulae(13-1) to (13-8), for example.

The anthracene derivative represented by the general formula (G11) ispreferably the anthracene derivative represented by the general formula(G14-1) or (G14-2), for easy synthesis and purification.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

Also, the anthracene derivative represented by the general formula (G21)is preferably the anthracene derivative represented by the generalformula (G24-1) or (G24-2) for easy synthesis and purification.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

In the formula, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, and R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms.

Further, in the anthracene derivative represented by the general formula(G11), it is preferable that Ar¹ and Ar² be independently a substitutedor unsubstituted phenyl group for easy synthesis and purification. Thatis, the anthracene derivative represented by the general formula (G15-1)or (G15-2) is preferable.

In the formula, R¹¹ represents hydrogen, an alkyl group having 1 to 4carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms, and R³¹ to R⁴⁰ independently represent hydrogen, analkyl group having 1 to 4 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 10 carbon atoms, halogen, or a haloalkyl grouphaving 1 to 4 carbon atoms.

In the formula, R²¹ and R²² independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, and R³¹ to R⁴⁰ independentlyrepresent hydrogen, an alkyl group having 1 to 4 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 10 carbon atoms,halogen, or a haloalkyl group having 1 to 4 carbon atoms.

Also, in the anthracene derivative represented by the general formula(G21), it is preferable that Ar¹ and Ar² be independently a substitutedor unsubstituted phenyl 5 group for easy synthesis and purification.That is, an anthracene derivative represented by the general formula(G25-1) or (G25-2) is preferable.

In the formula, R¹¹ represents hydrogen, an alkyl group having 1 to 4carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms, and R³¹ to R⁴⁰ independently represent hydrogen, analkyl group having 1 to 4 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 10 carbon atoms, halogen, or a haloalkyl grouphaving 1 to 4 carbon atoms.

In the formula, R²¹ and R²² independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, and R³¹ to R⁴⁰ independentlyrepresent hydrogen, an alkyl group having 1 to 4 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 10 carbon atoms,halogen, or a haloalkyl group having 1 to 4 carbon atoms.

As the haloalkyl group having 1 to 4 carbon atoms in each of the generalformulae (G15-1), (G15-2), (G25-1), and (G25-2), there is atrifluoromethyl group and the like.

Further, in the anthracene derivative represented by the general formula(G11), Ar¹ and Ar² are preferably substituents each having the samestructure, for easy synthesis and purification.

Also in the anthracene derivative represented by the general formula(G21), Ar¹ and Ar² are preferably substituents each having the samestructure, for easy synthesis and purification.

Specific examples of the anthracene derivative represented by thegeneral formula (G11) include, but not limited to, anthracenederivatives represented by structural formulae (101) to (149) and (201)to (242). Specific examples of the anthracene derivative represented bythe general formula (G21) include, but not limited to, anthracenederivatives represented by structural formulae (301) to (349) and (401)to (441).

The anthracene derivatives represented by the structural formulae (101)to (149) are specific examples in the case of the bond between Ar³ andAr⁴ or between Ar³ and Ar⁵ in the general formula (G11). The anthracenederivatives represented by the structural formulae (201) to (242) arespecific examples in the case of the bond between Ar⁴ and Ar⁵ in thegeneral formula (G11).

The anthracene derivatives represented by the structural formulae (301)to (349) are specific examples in the case of the bond between Ar³ andAr⁴ or between Ar³ and Ar⁵ in the general formula (G21). The anthracenederivatives represented by the structural formulae (401) to (441) arespecific examples in the case of the bond between Ar⁴ and Ar⁵ in thegeneral formula (G21).

A variety of reactions can be applied to methods of synthesizing theanthracene derivatives of the present invention. For example, theanthracene derivatives of the present invention can be synthesized bysynthesis reactions described hereinafter. Note that methods ofsynthesizing the anthracene derivatives of the present invention are notlimited to the synthesis methods below.

<Synthesis of Anthracene Derivative Represented by General Formula(G11)>

As illustrated in a synthesis scheme (A-1), an anthracene derivative(compound 1) and a carbazole derivative with a boronic acid ororganoboron (compound 2) are coupled by a Suzuki-Miyaura reaction,whereby an anthracene derivative in which a carbazole skeleton is bondedto the 2-position (compound 3), which is the object of the synthesis,can be obtained. In the synthesis scheme (A-1), X¹ represents halogen ora triflate group, Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms, Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms,Ar⁴ represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms, Ar⁵ represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms, and a direct bond between Ar³ and Ar⁴,between Ar³ and Ar⁵, or between Ar⁴ and Ar⁵ forms a five-membered ringto form a carbazole skeleton. In addition, in the case where X¹ ishalogen, X¹ is preferably chlorine, bromine, or iodine.

Examples of a palladium catalyst that can be used in the synthesisscheme (A-1) include, but not limited to, palladium(II) acetate,tetrakis(triphenylphosphine)palladium(0), and the like. Examples of aligand of the palladium catalyst which can be used in the synthesisscheme (A-1) include, but not limited to, tri(ortho-tolyl)phosphine,triphenylphosphine, tricyclohexylphosphine, and the like. Examples of abase that can be used in the synthesis scheme (A-1) include, but notlimited to, an organic base such as sodium t-butoxide, an inorganic basesuch as potassium carbonate, and the like. Examples of a solvent thatcan be used in the synthetic scheme (A-1) include, but not limited to, amixed solvent of toluene and water; a mixed solvent of toluene, alcoholsuch as ethanol, and water; a mixed solvent of xylene and water; a mixedsolvent of xylene, alcohol such as ethanol, and water; a mixed solventof benzene and water; a mixed solvent of benzene, alcohol such asethanol, and water; a mixed solvent of an ether such as ethylene glycoldimethyl ether and water; and the like. In addition, use of a mixedsolvent of toluene and water or a mixed solvent of toluene, ethanol, andwater is more preferable.

<Synthesis of Anthracene Derivative Represented by General Formula(G21)>

As illustrated in a synthesis scheme (A-2), an anthracene derivative(compound 4) and a carbazole derivative with a boronic acid ororganoboron (compound 2) are coupled by a Suzuki-Miyaura reaction,whereby an anthracene derivative in which two carbazole skeletons arebonded to the 2- and 6-positions (compound 5), which is the object ofthe synthesis, can be obtained. In the synthesis scheme (A-2), X² and X³independently represent halogen or a triflate group, Ar¹ and Ar²independently represent a substituted or unsubstituted aryl group having6 to 13 carbon atoms, Ar³ represents a substituted or unsubstitutedarylene group having 6 to 13 carbon atoms, Ar⁴ represents a substitutedor unsubstituted aryl group having 6 to 13 carbon atoms, Ar⁵ representsa substituted or unsubstituted aryl group having 6 to 13 carbon atoms,and a direct bond between Ar³ and Ar⁴, between Ar³ and Ar⁵, or betweenAr⁴ and Ar⁵ forms a five-membered ring to form a carbazole skeleton. Inaddition, in the case where X² and X³ are each halogen, X² and X³ arepreferably chlorine, bromine, or iodine and may be the same or differentfrom each other.

Examples of a palladium catalyst that can be used in the synthesisscheme (A-2) include, but not limited to, palladium(II) acetate,tetrakis(triphenylphosphine)palladium(0), and the like. Examples of aligand of the palladium catalyst which can be used in the synthesisscheme (A-2) include, but not limited to, tri(ortho-tolyl)phosphine,triphenylphosphine, tricyclohexylphosphine, and the like. Examples of abase that can be used in the synthesis scheme (A-2) include, but notlimited to, an organic base such as sodium t-butoxide, an inorganic basesuch as potassium carbonate, and the like. Examples of a solvent thatcan be used in the synthetic scheme (A-2) include, but not limited to, amixed solvent of toluene and water; a mixed solvent of toluene, alcoholsuch as ethanol, and water; a mixed solvent of xylene and water; a mixedsolvent of xylene, alcohol such as ethanol, and water; a mixed solventof benzene and water; a mixed solvent of benzene, alcohol such asethanol, and water; a mixed solvent of an ether such as ethylene glycoldimethyl ether and water; and the like. In addition, use of a mixedsolvent of toluene and water or a mixed solvent of toluene, ethanol, andwater is more preferable.

The anthracene derivatives of the present invention emit blue light withhigh color purity. Thus, each anthracene derivative is suitable for usein a light-emitting element. Furthermore, the anthracene derivatives ofthe present invention are stable against repetition of oxidationreactions and reduction reactions. Thus, by using any of the anthracenederivatives of the present invention for a light-emitting element, alight-emitting element with a long lifetime can be obtained. Also, sincethe anthracene derivatives of the present invention can emit blue lightwith high color purity, each anthracene derivative is suitable for usein a light-emitting element for a full-color display.

The anthracene derivatives of the present invention have solubility in awide variety of solvents, such as dichloroethane, chloroform,tetrahydrofuran, cyclohexanone, dimethylformamide, dimethyl sulfoxide,acetone, dioxane, anisole, ethyl acetate, toluene, xylene, tetralin,chlorobenzene, dichlorobenzene, fluorobenzene, etc. and nitrobenzene,pyridine, methyl isobutyl ketone, diglyme etc. Therefore, a layerincluding any of the anthracene derivatives of the present invention canbe formed by forming a film of a mixture of such a solvent and theanthracene derivative by a wet method.

Embodiment 2

In Embodiment 2, one embodiment of a light-emitting element using any ofthe anthracene derivatives of the present invention will be describedwith reference to FIGS. 1A and 1B.

A light-emitting element described in Embodiment 2 has a plurality oflayers between a pair of electrodes. The plurality of layers are a stackof layers each including a substance with a high carrier-injectingproperty or a substance having a high carrier-transporting property suchthat a light-emitting region is formed in a region away from theelectrodes, i.e., such that carriers recombine in an area away from theelectrodes.

In Embodiment 2, the light-emitting element includes a first electrode102, a second electrode 104, and an EL layer 103 formed between thefirst electrode 102 and the second electrode 104. Note that inEmbodiment 2, hereinafter, it is assumed that the first electrode 102functions as an anode and the second electrode 104 functions as acathode. In other words, in the description below, it is assumed thatlight emission is obtained when a voltage is applied to the firstelectrode 102 and the second electrode 104 so that the potential of thefirst electrode 102 is higher than that of the second electrode 104.

A substrate 101 is used as a support of the light-emitting element. Forthe substrate 101, glass, plastic, or the like can be used, for example.Note that any other material may be used as long as it functions as asupport of the light-emitting element. Note that when light emissionfrom the light-emitting element is extracted outside through thesubstrate, a light-transmitting substrate is preferably used as thesubstrate 101.

Preferably, the first electrode 102 is formed using any of metals,alloys, or electrically conductive compounds, a mixture thereof, or thelike having a high work function (specifically, greater than or equal to4.0 eV is preferable). For example, there are indium oxide-tin oxide(ITO), indium oxide-tin oxide containing silicon or silicon oxide,indium oxide-zinc oxide (IZO), indium oxide containing tungsten oxideand zinc oxide (IWZO), and the like. Films of such electricallyconductive metal oxide are normally formed by sputtering, but may alsobe formed by an inkjet method, a spin coating method, or the like byapplying a sol-gel method or the like. For example, a film of indiumoxide-zinc oxide (IZO) can be formed using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide by a sputtering method. Inaddition, a film of indium oxide containing tungsten oxide and zincoxide (IWZO) can be formed using a target in which 0.5 to 5 wt %tungsten oxide and 0.1 to 1 wt % zinc oxide are added to indium oxide bya sputtering method. Further, there are gold (Au), platinum (Pt), nickel(Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt(Co), copper (Cu), palladium (Pd), titanium (Ti), nitride of a metalmaterial (e.g., titanium nitride), and the like.

Further, when a layer including a composite material described later isused as a layer that is in contact with the first electrode 102, any ofa variety of metals, alloys, electrically conductive compounds, or amixture thereof can be used for the first electrode 102 regardless ofthe work functions. For example, aluminum (Al), silver (Ag), an alloycontaining aluminum (e.g., AlSi), or the like can be used.Alternatively, it is possible to use any of elements belonging to Group1 or 2 of the periodic table which have a low work function, i.e.,alkali metals such as lithium (Li) and cesium (Cs); alkaline earthmetals such as magnesium (Mg), calcium (Ca), and strontium (Sr); alloyscontaining any of these metals (e.g., MgAg and AlLi); rare earth metalssuch as europium (Eu) and ytterbium (Yb); alloys containing any of thesemetals; or the like. A film of an alkali metal, an alkaline earth metal,or an alloy containing any of these metals can be formed by a vacuumevaporation method. Alternatively, a film of an alloy containing analkali metal or an alkaline earth metal can be formed by a sputteringmethod. Further, a film can be formed using silver paste or the like byan inkjet method or the like.

The EL layer 103 described in Embodiment 2 includes a hole-injectinglayer 111, a hole-transporting layer 112, a light-emitting layer 113, anelectron-transporting layer 114, and an electron-injecting layer 115.Note that as long as the EL layer 103 includes any of the anthracenederivatives described in Embodiment 1, there is no limitation on thestack structure of the other layers. In other words, there is nolimitation on the stack structure of the EL layer 103 as long as the ELlayer 103 has a structure in which any of the anthracene derivativesdescribed in Embodiment 1 is used in combination with a layer includinga substance with a high electron-transporting property, a substance witha high hole-transporting property, a substance with a highelectron-injecting property, a substance with a high hole-injectingproperty, a bipolar substance (a substance with a highelectron-transporting property and a high hole-transporting property),or the like, as appropriate. For example, the structure can be formed bycombining a hole-injecting layer, a hole-transporting layer, alight-emitting layer, an electron-transporting layer, anelectron-injecting layer, etc., as appropriate. Materials for the layersare specifically given below.

The hole-injecting layer 111 is a layer including a substance with ahigh hole-injecting property. As a substance having a highhole-injecting property, molybdenum oxide, vanadium oxide, rutheniumoxide, tungsten oxide, manganese oxide, or the like can be used.Besides, as examples of low molecular organic compounds, there arephthalocyanine-based compounds such as phthalocyanine (abbreviation:H₂Pc), copper(II) phthalocyanine (abbreviation: CuPc), and vanadyl(IV)phthalocyanine (VOPc), aromatic amine compounds such as4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA),4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA),4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation:DPAB),4,4′-bis(N-{4-[N′-(3-methylphenyl)-N′-phenylamino]phenyl}-N-phenylamino)biphenyl(abbreviation: DNTPD),1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene(abbreviation: DPA3B),3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2), and3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1), and the like.

Alternatively, the hole-injecting layer 111 can be formed using acomposite material in which an acceptor substance is included in asubstance having a high hole-transporting property. Note that, by usinga material in which an acceptor substance is included in a substancehaving a high hole-transporting property, a material used for formingthe electrode may be selected regardless of the work function. In otherwords, besides a material with a high work function, a material with alow work function may also be used for the first electrode 102. Suchcomposite materials can be formed by co-evaporation of a substancehaving a high hole-transporting property and an acceptor substance.

Note that in this specification, the term “composite” refers not only toa state in which two kinds of materials are simply mixed, but also to astate in which charges can be given and received between materials bymixture of a plurality of materials.

As an organic compound used for the composite material, any of a varietyof compounds such as aromatic amine compounds, carbazole derivatives,aromatic hydrocarbons, or high molecular compounds (oligomers,dendrimers, polymers, etc.) can be used. Note that an organic compoundused for the composite material preferably has a high hole-transportingproperty. Specifically, a substance having a hole mobility of 10⁻⁶cm²/Vs or more is preferably used. Further, any other substance may beused as long as it is a substance in which the hole-transportingproperty is higher than the electron-transporting property. Organiccompounds that can be used for the composite material are specificallygiven below.

For example, any of the following organic compounds can be used for thecomposite material: aromatic amine compounds such as MTDATA, TDATA,DPAB, DNTPD, DPA3B, PCzPCA1, PCzPCA2, PCzPCN1,4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB orα-NPD), andN,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD); carbazole derivatives such as4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB),9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), and1,4-bis[4-(N-carbazolyl)phenyl-2,3,5,6-tetraphenylbenzene; and aromatichydrocarbon compounds such as 2-tert-butyl-9,10-di(2-naphthyl)anthracene(abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene,9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA),2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA),9,10-di(2-naphthyl)anthracene (abbreviation: DNA),9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene(abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene(abbreviation: DMNA),9,10-bis[2-(1-naphthyl)phenyl)-2-tert-butyl-anthracene,9,10-bis[2-(1-naphthyl)phenyl]anthracene,2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene,2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9′-bianthryl,10,10′-diphenyl-9,9′-bianthryl,10,10′-bis(2-phenylphenyl)-9,9′-bianthryl,10,10′-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9′-bianthryl, anthracene,tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene,pentacene, coronene, 4,4′-bis(2,2-diphenylvinyl)biphenyl (abbreviation:DPVBi), and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene(abbreviation: DPVPA).

Further, examples of the acceptor substance are as follows: organiccompounds such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane(abbreviation: F₄-TCNQ) and chloranil, and transition metal oxides.Furthermore, other examples are oxides of metals belonging to Group 4 toGroup 8 of the periodic table. Specifically, vanadium oxide, niobiumoxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide,manganese oxide, and rhenium oxide are preferable because of their highelectron-accepting properties. Among these, molybdenum oxide isespecially preferable because it is stable in air and its hygroscopicproperty is low so that it can be easily handled.

Alternatively, for the hole-injecting layer 111, any of high molecularcompounds (oligomers, dendrimers, polymers, etc.) can be used. Examplesof high molecular compounds include poly(N-vinylcarbazole)(abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA), andpoly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine (abbreviation:Poly-TPD). Alternatively, a high molecular compound to which acid isadded, such as poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonicacid) (PEDOT/PSS) or polyaniline/poly(styrenesulfonic acid) (PAni/PSS),can be used.

Alternatively, for the hole-injecting layer 111, a composite materialformed using any of the above-mentioned high molecular compounds such asPVK, PVTPA, PTPDMA, or Poly-TPD and any of the above-mentioned acceptorsubstances may be used.

The hole-transporting layer 112 is a layer including a substance with ahigh hole-transporting property. As a substance having a highhole-transporting property, a low molecular organic compound can beused, and examples thereof include aromatic amine compounds such as NPB(or α-NPD), TPD,4,4′-bis[N-(9,9-dimethylfluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: DFLDPBi), and4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB). The substances mentioned here are mainlysubstances having a hole mobility of 10⁻⁶ cm²/Vs or more. However, anyother substance may also be used as long as it is a substance in whichthe hole-transporting property is higher than the electron-transportingproperty. Note that the hole-transporting layer is not limited to asingle layer and may be a stack of two or more layers including any ofthe above-mentioned substances.

Alternatively, for the hole-transporting layer 112, a composite materialin which an acceptor substance is included in the above-mentionedsubstance having a high hole-transporting property may be used.

Alternatively, for the hole-transporting layer 112, a high molecularcompound such as PVK, PVTPA, PTPDMA, or Poly-TPD can be used.

The light-emitting layer 113 is a layer including a substance with ahigh light-emitting property. In the light-emitting element described inEmbodiment 2, the light-emitting layer 113 includes any of theanthracene derivatives of the present invention which are described inEmbodiment 1. Since the anthracene derivatives of the present inventionemit blue light with high color purity, each anthracene derivative issuitable for use in a light-emitting element as a substance with a highlight-emitting property.

The electron-transporting layer 114 is a layer including a substancewith a high electron-transporting property. As examples of low molecularcompounds, there are metal complexes such astris(8-quinolinolato)aluminum(III) (abbreviation: Alq),tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq₃),bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq₂),bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III)(abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq),bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), andbis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).Furthermore, besides the metal complexes, there are heterocycliccompounds such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviation: OXD-7),3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole(abbreviation: TAZ01), bathophenanthroline (abbreviation: BPhen), andbathocuproine (abbreviation: BCP). The substances mentioned here aremainly substances having an electron mobility of 10⁻⁶ cm²/Vs or more.Note that any other substance may also be used as long as it is asubstance in which the electron-transporting property is higher than thehole-transporting property. Further, the electron-transporting layer isnot limited to a single layer and may be a stack of two or more layersincluding any of the above-mentioned substances.

Alternatively, a high molecular compound can be used for theelectron-transporting layer 114. For example,poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation: PF-Py),poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation: PF-BPy), or the like can be used.

The electron-injecting layer 115 is a layer including a substance with ahigh electron-injecting property. As the substance having a highelectron-injecting property, any of alkali metals, alkaline earthmetals, or compounds thereof, such as lithium fluoride (LiF), cesiumfluoride (CsF), and calcium fluoride (CaF₂) can be used. Alternatively,a layer that includes a substance having an electron-transportingproperty and a substance exhibiting an electron-donating property withrespect to the substance having an electron-transporting property can beused. Specifically, a layer in which an alkali metal, an alkaline earthmetal, or a compound thereof is contained in a substance having anelectron-transporting property, such as a layer in which magnesium (g)is contained in Alq, can be used. Note that as the electron-injectinglayer, use of a layer that includes a substance having anelectron-transporting property and a substance exhibiting anelectron-donating property with respect to the substance having anelectron-transporting property is preferable in that injection ofelectrons from the second electrode 104 can be efficiently performed.

As a substance for forming the second electrode 104, a metal, an alloy,an electrically conductive compound, a mixture thereof, or the like witha low work function (specifically, a work function of 3.8 eV or less ispreferable) can be used. As specific examples of such cathode materials,there are elements belonging to Group 1 or Group 2 of the periodictable, i.e., alkali metals such as lithium (Li) and cesium (Cs);alkaline earth metals such as magnesium (Mg), calcium (Ca), andstrontium (Sr); alloys containing any of these metals (e.g., MgAg andAlLi); rare earth metals such as europium (Eu) and ytterbium (Yb);alloys containing any of these metals; and the like. A film of an alkalimetal, an alkaline earth metal, or an alloy containing any of thesemetals can be formed by a vacuum evaporation method. Alternatively, afilm of an alloy containing an alkali metal or an alkaline earth metalcan be formed by a sputtering method. Further, a film can be formedusing silver paste or the like by an inkjet method or the like.

Further, by providing the electron-injecting layer 115 which is a layerhaving the function of promoting injection of electrons between thesecond electrode 104 and the electron-transporting layer 114, the secondelectrode 104 can be formed using any of a variety of conductivematerials such as Al, Ag, ITO, or indium oxide-tin oxide containingsilicon or silicon oxide, regardless of the work functions. Films ofthese conductive materials can be formed by a sputtering method, aninkjet method, a spin coating method, or the like.

Further, any of a variety of methods can be employed for forming the ELlayer regardless of whether the method is a dry process or a wetprocess. For example, a vacuum evaporation method, an inkjet method, aspin coating method, or the like may be used. Further, a differentformation method may be used for each electrode or each layer.

For example, the EL layer may be formed using a high molecular compoundselected from the above-described materials by a wet method.Alternatively, the EL layer can be formed using a low molecular organiccompound by a wet method. Further alternatively, the EL layer may beformed using a low molecular organic compound by a dry method such asvacuum evaporation.

In addition, the electrode may be formed by a wet method using a sol-gelmethod, or by a wet method using paste of a metal material.Alternatively, the electrode may be formed by a dry method such as asputtering method or a vacuum evaporation method.

For example, in order that a display device to which a light-emittingelement of the present invention is applied may be manufactured using alarge substrate, light-emitting layers are preferably formed by a wetmethod. Even with a large substrate, use of an inkjet method for forminglight-emitting layers facilitates forming the light-emitting layers indifferent colors.

In the light-emitting element of the present invention which has astructure as described above, a current flows because of a potentialdifference applied between the first electrode 102 and the secondelectrode 104, and holes and electrons recombine in the EL layer 103,whereby light is emitted.

The emitted light is extracted out through one or both of the firstelectrode 102 and the second electrode 104. Therefore, one or both ofthe first electrode 102 and the second electrode 104 is/are an electrodehaving a light-transmitting property. For example, when only the firstelectrode 102 has a light-transmitting property, the emitted light isextracted from a substrate side through the first electrode 102.Alternatively, when only the second electrode 104 has alight-transmitting property, the emitted light is extracted from theside opposite to the substrate through the second electrode 104. Wheneach of the first electrode 102 and the second electrode 104 has alight-transmitting property, the emitted light is extracted from boththe substrate side and the side opposite to the substrate side throughthe first electrode 102 and the second electrode 104.

Note that the structure of layers provided between the first electrode102 and the second electrode 104 are not limited to the above structure.Any structure instead of the above structure can be employed as long asthe light-emitting region for recombination of electrons and holes ispositioned away from the first electrode 102 and the second electrode104 so as to prevent quenching due to the proximity of thelight-emitting region and a metal, and any of the anthracene derivativesdescribed in Embodiment 1 is included in the structure.

That is, there is no limitation on the stack structure of the layers, aslong as any of the anthracene derivatives of the present invention isused in combination with a layer including a substance with a highelectron-transporting property, a substance having a highhole-transporting property, a substance having a high electron-injectingproperty, a substance having a high hole-injecting property, or asubstance having a bipolar property (a substance having a highelectron-transporting property and a hole-transporting property), asappropriate.

In addition, as illustrated in FIG. 1B, over the substrate 101, thesecond electrode 104 functioning as a cathode, the EL layer 103, and thefirst electrode 102 functioning as an anode may be stacked in thatorder. In FIG. 1B, a structure is employed in which theelectron-injecting layer 115, the electron-transporting layer 114, thelight-emitting layer 113, the hole-transporting layer 112, and thehole-injecting layer 111 are stacked in that order over the secondelectrode 104.

Note that in Embodiment 2, the light-emitting element is fabricated overa substrate formed using glass, plastic, or the like. By fabrication ofa plurality of such light-emitting elements over one substrate, apassive matrix light-emitting device can be manufactured. Moreover, thelight-emitting element may be fabricated over an electrode that iselectrically connected to, for example, a thin film transistor (TFT)formed over a substrate formed using glass, plastic, or the like. Thus,an active matrix light-emitting device in which driving of alight-emitting element is controlled by a TFT can be manufactured. Notethat there is no limitation on the structure of a TFT, and either astaggered TFT or an inverted staggered TFT may be used. Further, adriving circuit formed over a TFT substrate may be formed using ann-channel TFT and a p-channel TFT, or may be formed using any one of ann-channel TFT or a p-channel TFT. Furthermore, there is no limitation onthe crystallinity of a semiconductor film used for the TFT. Either anamorphous semiconductor film or a crystalline semiconductor film may beused for the TFT. In addition, a single crystalline semiconductor filmmay be used. The single crystalline semiconductor film can be formed bya Smart Cut (registered trademark) method or the like.

Since the anthracene derivatives of the present invention emit bluelight with high color purity, each anthracene derivative can be used fora light-emitting layer, as described in Embodiment 2, without any otherlight-emitting substance. By using any of the anthracene derivatives ofthe present invention, a light-emitting element that emits blue lightwith high color purity can be obtained.

Further, since the anthracene derivatives of the present invention arestable against repetition of oxidation reactions and reductionreactions, by using any of the anthracene derivatives for alight-emitting element, a light-emitting element with a long lifetimecan be obtained.

Moreover, since a light-emitting element using any of the anthracenederivatives of the present invention can emit blue light with high colorpurity, the light-emitting element is suitable for use in a full-colordisplay. In particular, development of blue light-emitting elements lagsbehind that of red or green light-emitting elements in terms oflifetime, color purity, and efficiency, and blue light-emitting elementshaving good properties are desired. A light-emitting element using anyof the anthracene derivatives of the present invention can emit bluelight with a long lifetime and is suitable for a full-color display.

Furthermore, since the anthracene derivatives of the present inventionemit blue light with high color purity, a white light-emitting elementcan be obtained by combining any of the anthracene derivatives of thepresent invention with another light-emitting material and applying itto a light-emitting element.

Embodiment 3

In Embodiment 3, a structure that is different from the structuredescribed in Embodiment 2 will be described.

When the light-emitting layer 113 described in Embodiment 2 is formed bydispersing any of the anthracene derivatives of the present inventioninto another substance (host material), light emission from theanthracene derivative of the present invention can be obtained. Sincethe anthracene derivatives of the present invention emit blue light withhigh color purity, a light-emitting element that emits blue light withhigh color purity can be obtained.

Here, as a substance in which any of the anthracene derivatives of thepresent invention is dispersed, any of a wide variety of materials canbe used. Besides the substances having a high hole-transporting propertyor a high electron-transporting property which are given in Embodiment2, there are, for example, 4,4′-bis(N-carbazolyl)biphenyl (abbreviation:CBP), 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole)(abbreviation: TPBI), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA),2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA),9-[4-(10-phenyl-9-antliryl)phenyl]-9H-carbazole (abbreviation: CzPA),and the like. Alternatively, as a substance in which any of theanthracene derivatives of the present invention is dispersed, a highmolecular material can be used. For example, poly(N-vinylcarbazole)(abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA),poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation:Poly-TPD), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation: PF-Py),poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation: PF-BPy), or the like can be used.

Since the anthracene derivatives of the present invention emit bluelight with high color purity, any of the anthracene derivatives can beused as a light-emitting substance. By using any of the anthracenederivatives of the present invention, a light-emitting element thatemits blue light with high color purity can be obtained.

Further, since the anthracene derivatives of the present invention arestable against repetition of oxidation reactions and reductionreactions, by using any of the anthracene derivatives for alight-emitting element, a light-emitting element with a long lifetimecan be obtained.

Moreover, since a light-emitting element using any of the anthracenederivatives of the present invention can emit blue light with high colorpurity, the light-emitting element is suitable for use in a full-colordisplay. In particular, development of blue light-emitting elements lagsbehind that of red or green light-emitting elements in terms oflifetime, color purity, and efficiency, and blue light-emitting elementshaving good properties are desired. A light-emitting element using anyof the anthracene derivatives of the present invention can emit bluelight with a long lifetime and is suitable for a full-color display.

Note that for layers except the light-emitting layer 113, the structuredescribed in Embodiment 2 can be used as appropriate.

Embodiment 4

In Embodiment 4, a structure that is different from the structuresdescribed in Embodiments 2 and 3 will be described.

When the light-emitting layer 113 described in Embodiment 2 is formed bydispersing a light-emitting substance (guest material) into any of theanthracene derivatives of the present invention, light emission from thelight-emitting substance (guest material) can be obtained.

When any of the anthracene derivatives of the present invention is usedas a material in which another light-emitting substance is dispersed, anemission color from the light-emitting substance can be obtained.Alternatively, a mixed color of an emission color from the anthracenederivative of the present invention and the emission color from thelight-emitting substance dispersed in the anthracene derivative can beobtained.

Here, as a light-emitting substance that is to be dispersed in any ofthe anthracene derivatives of the present invention, any of a widevariety of materials can be used. Examples of fluorescent compoundswhich emit fluorescence are given below. Examples of materials for bluelight emission are as follows:N,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine(abbreviation: YGA2S),4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine(abbreviation: YGAPA), and the like. Further, examples of materials forgreen light emission are as follows:

-   N-(9,10-diphenyl-2-anthryl)-N,N′-diphenyl-9H-carbazol-3-amine    (abbreviation: 2PCAPA),-   N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine    (abbreviation: 2PCABPhA),-   N-(9,10-diphenyl-2-anthryl)-N,N′,N′-triphenyl-1,4-phenylenediamine    (abbreviation: 2DPAPA),-   N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,N′,N′-triphenyl-1,4-phenylenediamine    (abbreviation: 2DPABPhA),-   9,10-bis(1,1′-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine    (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine    (abbreviation: DPhAPhA), and the like. Further, examples of    materials for yellow light emission are as follows: rubrene,    5,12-bis(1,1′-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation:    BPT), and the like. Further, examples of materials for red light    emission are as follows:    N,N,N′,N′-tetrakis(4-methylphenyl)tetracene-5,11-diamine    (abbreviation: p-mPhTD),-   7,13-diphenyl-N,N,N′,N′-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,    10-diamine (abbreviation: p-mPhAFD),-   2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile    (abbreviation: DCM1),-   2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile    (abbreviation: DCM2), and the like. Further, examples of    phosphorescent compounds which emit phosphorescence include    bis[2-(2′-benzo[4,5-α]thienyl)pyridinato-N,C^(3′)]iridium(III)    acetylacetonate (abbreviation: Ir(btp)₂(acac)),    bis(1-phenylisoquinolinato-N,C^(2′))iridium(III) acetylacetonate    (abbreviation: Ir(piq)₂(acac)),    (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)    (abbreviation: Ir(Fdpq)₂(acac)),    2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II)    (abbreviation: PtOEP), and the like.

The anthracene derivatives of the present invention each have a largeenergy gap. Therefore, even when a light-emitting substance that emitslight at short wavelengths is dispersed in the anthracene derivative,light emission from the light-emitting substance can be obtained. Thatis, a substance that emits light at short wavelengths can be excited toemit light.

Further, the anthracene derivatives of the present invention are stableagainst repetition of oxidation reactions and reduction reactions.Accordingly, by using any of the anthracene derivatives of the presentinvention as a host material, a light-emitting element with a longlifetime can be obtained.

Note that for the layers except the light-emitting layer 113, thestructure described in Embodiment 2 can be used as appropriate.

Embodiment 5

In Embodiment 5, a structure that is different from the structuresdescribed in Embodiments 2 to 4 is described.

The anthracene derivatives of the present invention each have acarrier-transporting property and thus can be used for acarrier-transporting layer of a light-emitting element.

The anthracene derivatives of the present invention each have anelectron-transporting property. Thus, a layer including any of theanthracene derivatives of the present invention can be provided betweenthe cathode and the light-emitting layer. Specifically, any of theanthracene derivatives of the present invention can be used for theelectron-injecting layer 115 or the electron-transporting layer 114described in Embodiment 2.

Also, when any of the anthracene derivatives of the present invention isused for the electron-injecting layer 115, the electron-injecting layer115 preferably includes the anthracene derivative of the presentinvention and a substance having an electron-donating property withrespect to the anthracene derivative of the present invention. Such astructure improves the electron-injecting property. Also, a material forthe second electrode can be selected regardless of the work function. Asa substance having an electron-donating property with respect to theanthracene derivative of the present invention, an alkali metal, analkaline earth metal, or a compound thereof can be used.

Further, the anthracene derivatives of the present invention each have ahole-transporting property and thus can be used for thehole-transporting layer. Furthermore, a composite material in which anacceptor substance is contained in any of the anthracene derivatives ofthe present invention can be used for the hole-injecting layer or thehole-transporting layer. As an acceptor substance, any of the substancesgiven in Embodiment 2 can be used.

Note that Embodiment 5 can be combined with any other embodiment asappropriate.

Embodiment 6

In Embodiment 6, a structure that is different from the structuresdescribed in Embodiments 2 to 5 will be described using FIG. 2.

In a light-emitting element described in Embodiment 6, a functionallayer 116 is newly formed between the light-emitting layer 113 and theelectron-transporting layer 114 of the light-emitting element describedin Embodiment 2. The functional layer 116 controls the rate of transportof electrons injected from the second electrode 104.

The functional layer 116 includes a first organic compound and a secondorganic compound, and the amount of the first organic compound is largerthan the amount of the second organic compound. That is, the secondorganic compound is dispersed in the first organic compound. Further,the layer for controlling transport of electrons is preferably providedcloser to the second electrode 104 functioning as a cathode than thelight-emitting layer 113 is. That is, the layer for controllingtransport of electrons is preferably provided between the light-emittinglayer 113 and the second electrode 104.

For the functional layer 116, a plurality of structures can be given. Afirst example of the structures can be a structure in which a secondorganic compound having the function of trapping electrons is added intoa first organic compound having an electron-transporting property. Inthis structure, electrons are injected from the second electrode 104serving as a cathode into the functional layer 116 through theelectron-transporting layer and the like. The electrons injected intothe functional layer 116 are temporarily trapped by the second organiccompound, whereby the transport of the electrons is retarded; thus,injection of the electrons into the light-emitting layer 113 iscontrolled.

In this structure, the second organic compound included in thefunctional layer 116 is an organic compound having the function oftrapping electrons. Therefore, the lowest unoccupied molecular orbital(LUMO) level of the second organic compound is preferably lower than thelowest unoccupied molecular orbital (LUMO) level of the first organiccompound included in the functional layer 116 by 0.3 eV or more. Withthe second organic compound included in the functional layer 116, therate of transport of electrons in the whole layer is lower than the casewhere only the first organic compound is included in this layer. Thatis, by addition of the second organic compound, transport of carrierscan be controlled. Further, by control of the concentration of thesecond organic compound, the rate of transport of carriers can becontrolled. Specifically, the concentration of the second organiccompound is preferably in the range of 0.1 to 5 wt % or in the range of0.1 to 5 mol %.

As the second organic compound included in the functional layer 116, forexample, any of the following substances can be used:N,N′-dimethylquinacridone (abbreviation: DMQd),N,N′-diphenylquinacridone (abbreviation: DPQd),9,18-dihydro-benzo[h]benzo[7,8]quino[2,3-b]acridine-7,16-dione(abbreviation: DMNQd-1),9,18-dihydro-9,18-dimethyl-benzo[h]benzo[7,8]quino[2,3-b]acridine-7,16-dione(abbreviation: DMNQd-2), coumarin 30, coumarin 6, coumarin 545T,coumarin 153, and the like.

The first organic compound included in the functional layer 116 is anorganic compound having an electron-transporting property. That is, thefirst organic compound is a compound in which the electron-transportingproperty is higher than the hole-transporting property. Specifically,any of the following substances can be used: metal complexes such astris(8-quinolinolato)aluminum(III) (abbreviation: Alq), Almq₃, BeBq₂,BAlq, Znq, BAlq, ZnPBO, and ZnBTZ, heterocyclic compounds such as PBD,OXD-7, TAZ, TPBI, BPhen, and BCP, and condensed aromatic compounds suchas CzPA, DPCzPA, DPPA, DNA, t-BuDNA, BANT, DPNS, DPNS2, and TPB3. Amongthem, metal complexes that are each stable against electrons arepreferably used. Further, as mentioned earlier, the LUMO level of thesecond organic compound is preferably lower than the LUMO level of thefirst organic compound by 0.3 eV or more. Thus, as the first organiccompound, an organic compound may be selected as appropriate so as tosatisfy the above conditions, depending on what kind of organic compoundis used as the second organic compound.

In the light-emitting element of the present invention which has astructure as described above, a current flows because of a potentialdifference applied between the first electrode 102 and the secondelectrode 104, whereby holes and electrons recombine in the EL layer 103to emit light. Specifically, a light-emitting region is formed in aregion from the light-emitting layer 113 in the EL layer 103 to theinterface between the light-emitting layer 113 and the functional layer116. This principle is described below.

Electrons are injected from the second electrode 104 into the functionallayer 116 through the electron-injecting layer 115 and theelectron-transporting layer 114. The transport of the electrons injectedinto the functional layer 116 is retarded due to the second organiccompound having an electron-trapping property; thus, injection of theelectrons into the light-emitting layer 113 is controlled. As a result,a light-emitting region, which has conventionally been localized in thevicinity of the interface between the hole-transporting layer 112 andthe light-emitting layer 113, is formed in a region from thelight-emitting layer 113 to the vicinity of the interface between thelight-emitting layer 113 and the functional layer 116. Therefore,electrons are less likely to reach the hole-transporting layer 112 andto make it deteriorate. Similarly, since the light-emitting layer 113has an electron-transporting property, holes are less likely to reachthe electron-transporting layer 114 and to make it deteriorate.

A second example of the structures of the functional layer 116 can be astructure in which the first organic compound is included in greateramount than the second organic compound and the polarity of carrierstransported by the first organic compound is different from that ofcarriers transported by the second organic compound. In the case wherethe functional layer 116 is provided between the light-emitting layerand the second electrode serving as a cathode, it is preferable that thefirst organic compound be an organic compound having anelectron-transporting property, and the second organic compound be anorganic compound having a hole-transporting property. Further, thedifference between the lowest unoccupied molecular orbital level (LUMOlevel) of the first organic compound and the lowest unoccupied molecularorbital level (LUMO level) of the second organic compound is preferablyless than 0.3 eV, more preferably, 0.2 eV or less. That is,thermodynamically, it is preferable that electrons, which are carriers,be easily moved between the first organic compound and the secondorganic compound.

In this structure, as described above, the first organic compound ispreferably an organic compound having an electron-transporting property.Specifically, any of the following substances can be used: metalcomplexes such as Alq, Almq₃, BeBq₂, BAlq, Znq, ZnPBO, and ZnBTz;heterocyclic compounds such as PBD, OXD-7, TAZ, TPBI, BPhen, and BCP;and condensed aromatic compounds such as CzPA, DPCzPA, DPPA, DNA,t-BuDNA, BANT, DPNS, DPNS2, and TPB3.

Further, as the second organic compound, an organic compound having ahole-transporting property is preferably used. Specifically, any of thefollowing materials can be used: condensed aromatic hydrocarbons such as9,10-diphenylanthracene (abbreviation: DPAnth) and6,12-dimethoxy-5,11-diphenylchrysene; aromatic amine compounds such asN,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine(abbreviation: DPHPA),N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: PCAPA),N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}9H-carbazol-3-amine(abbreviation: PCAPBA),N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA), NPB (or α-NPD), TPD, DFLDPBi, and BSPB; andcompounds having an amino group such as coumarin 7 and coumarin 30.

With a combination as described above, transport of electrons from thefirst organic compound to the second organic compound or from the secondorganic compound to the first organic compound is suppressed, wherebythe rate of transport of electrons in the functional layer 116 can besuppressed.

Note that among the above combinations, a combination of a metal complexas the first organic compound and an aromatic amine compound as thesecond organic is preferable. A metal complex has a highelectron-transporting property and has large dipole moment, whereas anaromatic amine compound has a high hole-transporting property and has acomparatively small dipole moment. With a combination of such substancesthat are significantly different in dipole moment, the abovementionedeffect of suppressing transport of electrons can be further increased.Specifically, when the dipole moment of the first organic compound is P₁and the dipole moment of the second organic compound is P₂, acombination that satisfies one of the following expressions ispreferable:P ₁ /P ₂≧3P ₁ /P ₂≦0.33

In the light-emitting element of the present invention which has astructure as described above, a current flows because of a potentialdifference applied between the first electrode 102 and the secondelectrode 104, whereby holes and electrons recombine in the EL layer 103to emit light. Specifically, a light-emitting region is formed in aregion from the light-emitting layer 113 in the EL layer 103 to theinterface between the light-emitting layer 113 and the functional layer116. This principle is described below.

In the functional layer 116, electrons are easy to inject into the firstorganic compound, which is an organic compound having anelectron-transporting property, and easy to transport toward theneighboring first organic compound. That is, the rate (ν) at whichelectrons are transported between the first organic compounds is high.

On the other hand, since the second organic compound, which is anorganic compound having a hole-transporting property, has the LUMO levelclose to the LUMO level of the first organic compound, it is possiblethat electrons will be thermodynamically injected into the first organiccompound. However, the rate (ν₁) at which electrons are injected fromthe first organic compound, which is an organic compound having anelectron-transporting property, into the second organic compound, whichis an organic compound having a hole-transporting property, or the rate(ν₂) at which electrons are injected from the second organic compoundinto the first organic compound is lower than the rate (ν) at whichelectrons are transported between the first organic compounds.

Therefore, since the functional layer 116 includes the second organiccompound, the rate of transport of electrons in the whole layer is lowerthan that in a layer including only the first organic compound. That is,by addition of the second organic compound, transport of carriers can becontrolled. Further, by control of the concentration of the secondorganic compound, the rate of transport of carriers can be controlled.

In a conventional light-emitting element in which the functional layer116 having either one of the above structures is not formed, electronsinjected from the second electrode are injected into the light-emittinglayer 113 while the transport of the electrons is not retarded. Theelectrons injected into the light-emitting layer 113 could reach thehole-transporting layer 112 by passing through the light-emitting layer,when the light-emitting layer 113 has an electron-transporting property,i.e., when the material the amount of which is the largest in thelight-emitting layer 113 has an electron-transporting property. Ifelectrons reach the hole-transporting layer 112, a material included inthe hole-transporting layer 112 could deteriorate, leading todeterioration of the light-emitting element. Further, if thisdeterioration increases the number of holes that reach theelectron-transporting layer 114 over time, recombination probability inthe light-emitting layer 113 is decreased over time, which results in areduction in element lifetime (luminance decay over time).

A feature of the light-emitting element described in Embodiment 6 isthat the functional layer 116 is further provided. Electrons injectedfrom the second electrode 104 are injected into the functional layer 116through the electron-injecting layer 115 and the electron-transportinglayer 114. Transport of the electrons injected into the functional layer116 is retarded, whereby injection of the electrons into thelight-emitting layer 113 is controlled. As a result, a light-emittingregion, which has conventionally been localized in the vicinity of theinterface between the hole-transporting layer 112 and the light-emittinglayer 113, is formed in a region from the light-emitting layer 113 tothe vicinity of the interface between the light-emitting layer 113 andthe functional layer 116. Therefore, electrons are less likely to reachthe hole-transporting layer 112 and to make it deteriorate. Similarly,since the light-emitting layer 113 has an electron-transportingproperty, holes are less likely to reach the electron-transporting layer114 and to make it deteriorate.

Furthermore, with an electron-blocking layer provided between the anodeand the light-emitting layer in order to prevent electrons from passingthrough the light-emitting layer as in a conventional case, thedeterioration of the function of blocking electrons of theelectron-blocking layer over time expands the recombination region tothe inside of the electron-blocking layer (or inside of thehold-transporting layer). Accordingly, current efficiency issignificantly decreased (i.e., luminance decays). On the other hand, inthe light-emitting element described in Embodiment 6, since transport ofelectrons is controlled before electrons reach the light-emitting layer(between the light-emitting layer and the cathode), the recombinationprobability in the light-emitting layer is not easily changed even iftransport of electrons is somewhat unbalanced with respect to transportof holes, whereby luminance does not easily decay.

Furthermore, it is an important point of Embodiment 6 that thefunctional layer 116 is formed by adding an organic compound having thefunction of trapping electrons or an organic compound having ahole-transporting property into an organic compound having anelectron-transporting property, instead of by applying only a substancewith low electron mobility. Such a structure enables not only control ofthe number of electrons injected into the light-emitting layer 113 butalso suppression of a change over time in the controlled number of theinjected electrons.

As described above, by controlling the number of electrons injected intothe light-emitting layer, a phenomenon that carrier balance is decreasedover time to lower the recombination probability can be prevented. Thisleads to an improvement of element lifetime (suppression of luminancedecay over time).

Further, since the layer for controlling transport of carriers which isdescribed in Embodiment 6 includes two or more kinds of substances, thecarrier balance can be precisely controlled by controlling thecombination or mixture ratio of the substances, the thickness of thelayer, etc.

Furthermore, since the carrier balance can be controlled by controllingthe combination or mixture ratio of the substances, the thickness of thelayer, etc., the carrier balance can be more easily controlled than by aconventional technique. That is, without any change in a physicalproperty of the substance, transport of carriers can be controlled witha mixture ratio of the substances, the thickness of the layer, etc.

Moreover, transport of carriers is controlled by using the organiccompound the amount of which is the smallest of those of the two or morekinds of substances included in the layer for controlling transport ofcarriers. That is, the transport of carriers can be controlled with thecomponent the amount of which is the smallest of those of the componentsincluded in the layer for controlling transport of carriers.Accordingly, a light-emitting element that does not easily deteriorateover time and has improved lifetime can be realized. In other words, ascompared with the case where carrier balance is controlled by a singlesubstance, carrier balance is not easily changed. For example, iftransport of carriers is controlled with a layer formed using a singlesubstance, the carrier balance of the whole layer is changed by apartial change in morphology, partial crystallization, or the like.Thus, the layer for controlling transport of carriers in that caseeasily deteriorates over time. However, by controlling the transport ofcarriers with the use of the component the amount of which is thesmallest of those of the components included in the layer forcontrolling transport of carriers, as described in Embodiment 6,influence of a change in morphology, crystallization, aggregation, orthe like is reduced, and thus a change over time is not easily caused.Thus, a light-emitting element with a long lifetime in which carrierbalance is not easily lost over time and accordingly emission efficiencyis not easily decreased over time can be obtained.

Further, the thickness of the functional layer 116 is preferably greaterthan or equal to 5 nm and less than or equal to 20 nm. If the functionallayer 116 is too thick, transport of electrons is slowed too much,resulting in an increase in driving voltage. Alternatively, if thefunctional layer 116 is too thin, the function of controlling transportof electrons cannot be achieved. Therefore, the thickness of thefunctional layer 116 is preferably greater than or equal to 5 nm andless than or equal to 20 nm.

Furthermore, since the functional layer controls transport of electrons,the layer is preferably provided between the light-emitting layer andthe electrode functioning as a cathode. More preferably, the functionallayer is provided so as to be in contact with the light-emitting layer.By providing the functional layer in contact with the light-emittinglayer, injection of electrons into the light-emitting layer can bedirectly controlled. Accordingly, a change in the carrier balance in thelight-emitting layer over time can be more suppressed, whereby a largereffect on improving the lifetime of the light-emitting element can beobtained. Furthermore, the process can be simplified.

Further, the functional layer is preferably provided so as to be incontact with the light-emitting layer. In such a case, the first organiccompound included in the functional layer is preferably different inkind from an organic compound the amount of which is large in thelight-emitting layer. In particular, in the case where thelight-emitting layer includes a substance in which a substance having ahigh light-emitting property is dispersed (host material) and thesubstance having a high light-emitting property (guest material), thehost material and the first organic compound are preferably different inkind. With such a structure, transport of electrons from the functionallayer to the light-emitting layer can be suppressed also between thefirst organic compound and the host material. Accordingly, the effectobtained by providing the layer for controlling transport of electronscan be further increased.

Since the anthracene derivatives of the present invention each have anelectron-transporting property, any of the anthracene derivatives can besuitably used as a substance in which a light-emitting substance isdispersed (host material) for a light-emitting layer of thelight-emitting element described in Embodiment 6. As the light-emittingsubstance that is to be dispersed in the anthracene derivative of thepresent invention (guest material), for example, any of the substancesgiven in Embodiment 4 can be used.

Note that a layer may be formed between the light-emitting layer 113 andthe functional layer 116 for controlling transport of electrons.

In the light-emitting element of Embodiment 6, the emission color of asubstance having a high light-emitting property which is included in thelight-emitting layer and the emission color of the second organiccompound are preferably similar colors. This can keep the color purityof the light-emitting element even if the second organic compoundunintendedly emits light. However, the second organic compound does notnecessarily emit light. For example, in the case where emissionefficiency of the substance having a high light-emitting property ishigher, the concentration of the second organic compound in thefunctional layer 116 for controlling transport of electrons ispreferably adjusted so that light emission from substantially only thesubstance having a high light-emitting property can be obtained (theconcentration of the second organic compound is slightly reduced so thatlight emission from the second organic compound can be suppressed). Inthis case, the emission color of the substance having a highlight-emitting property and the emission color of the second organiccompound are similar colors (i.e., they have substantially the samelevel of energy gap). Therefore, energy is difficult to transfer fromthe substance having a high light-emitting property toward the secondorganic compound, whereby high emission efficiency can be obtained.

Alternatively, the second organic compound preferably emits light at ashorter wavelength than the substance having a high light-emittingproperty which is included in the light-emitting layer. That is, thepeak wavelength of the second organic compound is preferably shorterthan the peak wavelength of the substance having a high light-emittingproperty which is included in the light-emitting layer. In that case,the energy gap of the second organic compound is larger than the energygap of the substance having a high light-emitting property. Accordingly,energy is difficult to transfer from the substance having a highlight-emitting property toward the second organic compound; therefore,unintended light emission from the second organic compound can besuppressed.

Note that Embodiment 6 can be combined with any other embodiment asappropriate.

Embodiment 7

In Embodiment 7, a light-emitting element in which a plurality oflight-emitting units according to the present invention are stacked(hereinafter, referred to as a stacked type element) is described withreference to FIG. 3. This light-emitting element is a stacked-typeelement including a plurality of light-emitting units between a firstelectrode and a second electrode. The structure of each light-emittingunit can be similar to those described in Embodiments 2 to 6. In otherwords, the light-emitting element described in Embodiments 2 to 6 areeach a light-emitting element having one light-emitting unit. As long asthe light-emitting unit includes at least a light-emitting layer, thereis no particular limitation on the stack structure of other layers. InEmbodiment 7, a light-emitting element having a plurality oflight-emitting units will be described.

In FIG. 3, a first light-emitting unit 511 and a second light-emittingunit 512 are stacked between a first electrode 501 and a secondelectrode 502, and a charge generation layer 513 is provided between thefirst light-emitting unit 511 and the second light-emitting unit 512.Electrodes that are similar to the electrodes of Embodiment 2 can beapplied to the first electrode 501 and the second electrode 502.Further, the first light-emitting unit 511 and the second light-emittingunit 512 may have either the same or different structure, which can besimilar to those described in Embodiments 2 to 6.

The charge generation layer 513 is a layer that injects electrons into alight-emitting unit on one side and injects holes into a light-emittingunit on the other side when a voltage is applied to the first electrode501 and the second electrode 502, and may be either a single layer or astack of plural layers. As a stack structure of plural layers, astructure in which a layer that injects holes and a layer that injectselectrons are stacked is preferable.

As the layer that injects holes, a semiconductor or an insulator, suchas molybdenum oxide, vanadium oxide, rhenium oxide, or ruthenium oxide,can be used. Alternatively, a structure may be employed in which anacceptor substance is added to a substance having a highhole-transporting property. The layer including a substance with a highhole-transporting property and an acceptor substance is formed using thecomposite material described in Embodiment 2 and includes, as theacceptor substance, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane(abbreviation: F₄-TCNQ) or metal oxide such as vanadium oxide,molybdenum oxide, or tungsten oxide. As the substance having a highhole-transporting property, any of a variety of compounds such asaromatic amine compounds, carbazole derivatives, aromatic hydrocarbons,or high molecular compounds (oligomers, dendrimers, polymers, etc.) canbe used. Note that a substance having a hole mobility of 10⁻⁶ cm²/Vs ormore is preferably applied to the substance having a highhole-transporting property. However, any other substance may also beused as long as it is a substance in which the hole-transportingproperty is higher than the electron-transporting property. Since thecomposite material of the substance having a high hole-transportingproperty and the acceptor substance has an excellent carrier-injectingproperty and an excellent carrier-transporting property, low-voltagedriving and low-current driving can be realized.

As the layer that injects electrons, an insulator or a semiconductor,such as lithium oxide, lithium fluoride, or cesium carbonate, can beused. Alternatively, a structure may be employed in which a donorsubstance is added to a substance having a high electron-transportingproperty. As the donor substance, an alkali metal, an alkaline earthmetal, a rare earth metal, a metal belonging to Group 13 of the periodictable, or an oxide or carbonate thereof can be used. Specifically,lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb),indium (In), lithium oxide, cesium carbonate, or the like is preferablyused. Alternatively, an organic compound such as tetrathianaphthacenemay be used as the donor substance. As the substance having a highelectron-transporting property, any of the materials given in Embodiment2 can be used. Note that a substance having an electron mobility of 10⁻⁶cm²/Vs or more is preferably applied to the substance having a highelectron-transporting property. However, any other substance may also beused as long as it is a substance in which the electron-transportingproperty is higher than the hole-transporting property. Since thecomposite material of the substance having a high electron-transportingproperty and the donor substance has an excellent carrier-injectingproperty and an excellent carrier-transporting property, low-voltagedriving and low-current driving can be realized.

Further, for the charge generation layer 513, any of the electrodematerials given in Embodiment 2 can be used. For example, the chargegeneration layer 513 may be formed using a layer including a substancewith a hole-transporting property and metal oxide in combination with atransparent conductive film. Note that the charge generation layer ispreferably a layer having a high light-transmitting property in terms oflight extraction efficiency.

In any case, the charge generation layer 513 interposed between thefirst light-emitting unit 511 and the second light-emitting unit 512 mayhave any structure as long as electrons can be injected into thelight-emitting unit on one side and holes can be injected into thelight-emitting unit on the other side when a voltage is applied betweenthe first electrode 501 and the second electrode 502. For example, anystructure is acceptable as long as the charge generation layer 513injects electrons into the first light-emitting unit 511 and injectsholes into the second light-emitting unit 512 when a voltage is appliedso that the potential of the first electrode is higher than that of thesecond electrode.

In Embodiment 7, the light-emitting element having two light-emittingunits is described. However, the present invention can be applied to alight-emitting element in which three or more light-emitting units arestacked, in a similar manner. As in the light-emitting element accordingto Embodiment 7, by arranging a plurality of light-emitting unitsbetween a pair of electrodes so that the plurality of light-emittingunits can be partitioned by a charge generation layer, light emission ina high luminance region can be achieved with current density kept low;thus, a light-emitting element having a long lifetime can be realized.Further, when the light-emitting element is applied to a lightingapparatus, voltage drop due to the resistance of the electrode materialscan be suppressed; thus, uniform light emission in a large area can beachieved. Furthermore, a light-emitting device capable of low-voltagedriving with low power consumption can be realized.

Further, by forming light-emitting units to emit light of differentcolors from each other, a light-emitting element as a whole can providelight emission of a desired color. For example, by forming alight-emitting element having two light-emitting units such that theemission color of the first light-emitting unit and the emission colorof the second light-emitting unit are complementary to each other, thelight-emitting element can provide white light emission as a whole. Notethat “complementary colors” refer to colors that can produce anachromatic color when mixed. In other words, when light emitted fromsubstances that emit light of complementary colors is mixed, white lightemission can be obtained. Further, the same can be applied to alight-emitting element having three light-emitting units. For example,the light-emitting element as a whole can provide white light emissionwhen the emission color of the first light-emitting unit is red, theemission color of the second light-emitting unit is green, and theemission color of the third light-emitting unit is blue.

Note that Embodiment 7 can be combined with any other embodiment asappropriate.

Embodiment 8

In Embodiment 8, a light-emitting device manufactured using any of theanthracene derivatives of the present invention will be described.

In Embodiment 8, a light-emitting device manufactured using any of theanthracene derivatives of the present invention is described using FIGS.4A and 4B. Note that FIG. 4A is a top view illustrating thelight-emitting device and FIG. 4B is a cross-sectional view of FIG. 4Ataken along lines A-A′ and B-B′. This light-emitting device includes adriver circuit portion (a source side driver circuit) 601, a pixelportion 602, and a driver circuit portion (a gate side driver circuit)603, which are indicated by dotted lines, in order to control the lightemission from the light-emitting element. Further, reference numeral 604denotes a sealing substrate and reference numeral 605 denotes a sealingmaterial. Reference numeral 607 denotes a space surrounded by thesealing material 605.

Note that a leading wiring 608 is a wiring for transmitting signals thatare input to the source side driver circuit 601 and the gate side drivercircuit 603. The leading wiring 608 receives video signals, clocksignals, start signals, reset signals, and the like from an flexibleprinted circuit (FPC) 609 serving as an external input terminal. Notethat although only an FPC is illustrated here, this FPC may be providedwith a printed wiring board (PWB). The light-emitting device in thisspecification includes not only a light-emitting device itself but alsoa light-emitting device to which an FPC or a PWB is attached.

Then, a cross-sectional structure is described using FIG. 4B. The drivercircuit portions and the pixel portion are provided over an elementsubstrate 610, but only the source side driver circuit 601, which is thedriver circuit portion, and one pixel of the pixel portion 602 areillustrated.

Further, a CMOS circuit which is a combination of an n-channel TFT 623and a p-channel TFT 624 is formed in the source side driver circuit 601.The driver circuit may be formed using various types of circuits such asCMOS circuits, PMOS circuits, or NMOS circuits. Furthermore, inEmbodiment 8, a driver-integrated type in which a driver circuit isformed over a substrate provided with a pixel portion is described;however, the present invention is not limited to this type, and thedriver circuit can be formed outside the substrate instead of beingformed over the substrate provided with the pixel portion.

Further, the pixel portion 602 includes a plurality of pixels eachhaving a switching TFT 611, a current controlling TFT 612, and a firstelectrode 613 which is electrically connected to a drain of the currentcontrolling TFT 612. Note that an insulator 614 is formed to cover anend portion of the first electrode 613. Here, a positive photosensitiveacrylic resin film is used to form the insulator 614.

Further, in order to improve coverage, the insulator 614 is providedsuch that either an upper end portion or a lower end portion of theinsulator 614 has a curved surface with a curvature. For example, when apositive photosensitive acrylic resin is used as a material for theinsulator 614, it is preferable that only an upper end portion of theinsulator 614 have a curved surface with a radius of curvature (0.2 to 3μm). Alternatively, the insulator 614 can be formed using either anegative type resin that becomes insoluble in an etchant by lightirradiation or a positive type resin that becomes soluble in an etchantby light irradiation.

An EL layer 616 and a second electrode 617 are formed over the firstelectrode 613. Here, any of a variety of metals, alloys, electricallyconductive compounds, or a mixture thereof can be used for a material ofthe first electrode 613. If the first electrode is used as an anode, itis preferable that the first electrode be formed using, among suchmaterials, any of metals, alloys, or electrically conductive compounds,a mixture thereof, or the like having a high work function (preferably,a work function of 4.0 eV or more) among such materials. For example,the first electrode 613 can be formed using a single-layer film such asan indium oxide-tin oxide film containing silicon, an indium oxide-zincoxide film, a titanium nitride film, a chromium film, a tungsten film, aZn film, a Pt film, or the like; a stack of a titanium nitride film anda film containing aluminum as the main component; or a three-layerstructure of a titanium nitride film, a film containing aluminum as themain component, and a titanium nitride film. Note that with a stackstructure, the first electrode 613 has low resistance as a wiring, formsa favorable ohmic contact, and can serve as an anode.

Further, the EL layer 616 is formed by various methods such as anevaporation method with an evaporation mask, an inkjet method, a spincoating method, or the like. The EL layer 616 includes any of theanthracene derivatives described in Embodiment 1. Further, as anothermaterial included in the EL layer 616, any of low molecular compounds orhigh molecular compounds (the category includes oligomers, dendrimers,polymers, etc.) may be used. Furthermore, the material used for the ELlayer is not limited to an organic compound and may be an inorganiccompound.

Further, as the material for the second electrode 617, various types ofmetals, alloys, or electrically conductive compounds, a mixture thereof,or the like can be used. If the second electrode is used as a cathode,it is preferable that the second electrode be formed using, among suchmaterials, any of metals, alloys, or electrically conductive compounds,a mixture thereof, or the like having a low work function (preferably, awork function of 3.8 eV or less). For example, there are elementsbelonging to Group 1 and Group 2 of the periodic table, that is, alkalimetals such as lithium (Li) and cesium (Cs); alkaline earth metals suchas magnesium (Mg), calcium (Ca), and strontium (Sr); alloys containingany of these metals (e.g., MgAg and AlLi); and the like. When lightgenerated in the EL layer 616 is transmitted through the secondelectrode 617, the second electrode 617 can also be formed using a stackof a thin metal film with a small thickness and a transparent conductivefilm (indium oxide-tin oxide (ITO), indium oxide-tin oxide containingsilicon or silicon oxide, indium oxide-zinc oxide (IZO), indium oxidecontaining tungsten oxide and zinc oxide (IWZO), or the like).

Furthermore, by attaching the sealing substrate 604 and the elementsubstrate 610 to each other with the sealing material 605, alight-emitting element 618 is provided in the space 607 surrounded bythe element substrate 610, the sealing substrate 604, and the sealingmaterial 605. Note that the space 607 is filled with a filler. There arecases where the space 607 may be filled with an inert gas (e.g.,nitrogen or argon), or where the space 607 may be filled with thesealing material 605.

Note that as the sealing material 605, an epoxy-based resin ispreferably used. In addition, it is preferable that such a materialallows as little moisture or oxygen as possible to permeate. Further, asa material for the sealing substrate 604, a plastic substrate formedusing fiberglass-reinforced plastics (FRP), polyvinyl fluoride (PVF),polyester, acrylic, or the like can be used instead of a glass substrateor a quartz substrate.

As described above, the light-emitting device including thelight-emitting element of the present invention can be obtained.

Since any of the anthracene derivatives described in Embodiment 1 isused for the light-emitting device of the present invention, a highperformance light-emitting device can be obtained. Specifically, alight-emitting device with a long lifetime can be obtained.

Moreover, since the anthracene derivatives of the present invention canemit blue light with high color purity, each anthracene derivative issuitable for use in a full-color display. By using any of the anthracenederivatives of the present invention as a light-emitting substance for afull-color display, a display device with excellent colorreproducibility can be obtained.

As described above, in Embodiment 8, although an active matrixlight-emitting device which controls driving of a light-emitting elementwith a transistor is described, the light-emitting device may be apassive matrix light-emitting device. FIGS. 5A and 5B illustrate apassive matrix light-emitting device manufactured according to thepresent invention. Note that FIG. 5A is a perspective view of thelight-emitting device and FIG. 5B is a cross-sectional view of FIG. 5Ataken along a line X-Y. In FIGS. 5A and 5B, an EL layer 955 is providedbetween an electrode 952 and an electrode 956 over a substrate 951. Anend portion of the electrode 952 is covered with an insulating layer953. In addition, a partition layer 954 is provided over the insulatinglayer 953. The sidewalls of the partition layer 954 slope so that thedistance between one sidewall and the other sidewall gradually decreasestoward the surface of the substrate. In other words, a cross sectiontaken along the direction of the short side of the partition layer 954is trapezoidal, and the lower side (a side in contact with theinsulating layer 953, which is one of a pair of parallel sides of thetrapezoidal cross section) is shorter than the upper side (a side not incontact with the insulating layer 953, which is the other of the pair ofparallel sides). Providing the partition layer 954 in this mannerenables patterning of the EL layer 955 and the electrode 956. Also inthe case of a passive matrix light-emitting device, by using thelight-emitting element of the present invention, a light-emitting devicewith a long lifetime and/or high color reproducibility can be obtained.

Note that Embodiment 8 can be combined with any other embodiment asappropriate.

Embodiment 9

In Embodiment 9, electronic appliances of the present invention whicheach include the light-emitting device described in Embodiment 8 will bedescribed. Electronic appliances of the present invention each have adisplay portion that includes any of the anthracene derivativesdescribed in Embodiment 1 and has a long lifetime.

As examples of electronic appliances that each include a light-emittingelement fabricated using any of the anthracene derivatives of thepresent invention, there are televisions, cameras such as video camerasand digital cameras, goggle type displays (head-mounted displays),navigation systems, audio replay devices (e.g., car audio systems andaudio systems), computers, game machines, portable information terminals(e.g., mobile computers, cellular phones, portable game machines, andelectronic book readers), image replay devices in which a recordingmedium is provided (devices that are capable of replaying recordingmedia such as digital versatile discs (DVDs) and equipped with a displaydevice that can display an image), and the like. Specific examples ofthese electronic appliances are illustrated in FIGS. 6A to 6D.

FIG. 6A illustrates a television set according to the present invention,which includes a housing 9101, a supporting base 9102, a display portion9103, speaker portions 9104, a video input terminal 9105, and the like.In the display portion 9103 of this television set, light-emittingelements similar to those described in Embodiments 2 to 7 are arrangedin matrix. A feature of the light-emitting elements is a long lifetime.Since the display portion 9103 including the light-emitting elements hasa feature similar to that of the light-emitting elements, in thistelevision set, the amount of deterioration in image quality is small.With such a feature, deterioration compensation functional circuits andpower supply circuits in the television set can be greatly reduced ordownsized; accordingly, a reduction in the size and weight of thehousing 9101 or the supporting base 9102 can be achieved. In thetelevision set according to the present invention, higher image qualityand a reduction in size and weight are achieved; thus, a product that issuitable for living environment can be provided. Further, since theanthracene derivatives described in Embodiment 1 can emit blue lightwith high color purity, a television set having a display portion withhigh color reproducibility can be obtained.

FIG. 6B illustrates a computer according to the present invention, whichincludes a main body 9201, a housing 9202, a display portion 9203, akeyboard 9204, an external connection port 9205, a pointing device 9206,and the like. In the display portion 9203 of this computer,light-emitting elements similar to those described in Embodiments 2 to 7are arranged in matrix. A feature of the light-emitting elements is along lifetime. Since the display portion 9203 including thelight-emitting elements has a feature similar to that of thelight-emitting elements, in this computer, the amount of deteriorationin image quality is small. With such a feature, deteriorationcompensation functional circuits and power supply circuits in thecomputer can be greatly reduced or downsized; accordingly, a reductionin the size and weight of the main body 9201 and the housing 9202 can beachieved. In the computer according to the present invention, higherimage quality and a reduction in size and weight are achieved; thus, aproduct that is suitable for the environment can be provided. Further,since the anthracene derivatives described in Embodiment 1 can emit bluelight with high color purity, a computer having a display portion withhigh color reproducibility can be obtained.

FIG. 6C illustrates a camera according to the present invention, whichincludes a main body 9301, a display portion 9302, a housing 9303, anexternal connection port 9304, a remote control receiving portion 9305,an image receiving portion 9306, a battery 9307, an audio input portion9308, operation keys 9309, an eyepiece portion 9310, and the like. Inthe display portion 9302 of this camera, light-emitting elements similarto those described in Embodiments 2 to 7 are arranged in matrix. Afeature of the light-emitting elements is a long lifetime. Since thedisplay portion 9302 including the light-emitting elements has a featuresimilar to that of the light-emitting elements, in this camera, theamount of deterioration in image quality is small. With such a feature,deterioration compensation functional circuits and power supply circuitsin the camera can be greatly reduced or downsized; accordingly, areduction in the size and weight of the main body 9301 can be achieved.In the camera according to the present invention, higher image qualityand a reduction in size and weight are achieved; thus, a product that issuitable for being carried can be provided. Further, since theanthracene derivatives described in Embodiment 1 can emit blue lightwith high color purity, a camera having a display portion with highcolor reproducibility can be obtained.

FIG. 6D illustrates a cellular phone according to the present invention,which includes a main body 9401, a housing 9402, a display portion 9403,an audio input portion 9404, an audio output portion 9405, operationkeys 9406, an external connection port 9407, an antenna 9408, and thelike. In the display portion 9403 of this cellular phone, light-emittingelements similar to those described in Embodiments 2 to 7 are arrangedin matrix. A feature of the light-emitting elements is a long lifetime.Since the display portion 9403 including the light-emitting elements hasa feature similar to that of the light-emitting elements, in thiscellular phone, the amount of deterioration in image quality is small.With such a feature, deterioration compensation functional circuits andpower supply circuits in the cellular phone can be greatly reduced ordownsized; accordingly, a reduction in the size and weight of the mainbody 9401 and the housing 9402 can be achieved. In the cellular phoneaccording to the present invention, higher image quality and a reductionin size and weight are achieved; thus, a product that is suitable forbeing carried can be provided. Further, since the anthracene derivativesdescribed in Embodiment 1 can emit blue light with high color purity, amobile phone having a display portion with high color reproducibilitycan be obtained.

FIGS. 12A to 12C illustrate an example of a cellular phone having astructure, which is different from the structure of the cellular phonein FIG. 6D. FIG. 12A is a front view, FIG. 12B is a rear view, and FIG.12C is a development view. The cellular phone in FIGS. 12A to 12C is aso-called smartphone which has both a function of a phone and a functionof a portable information terminal, and incorporates a computer toconduct a variety of data processing in addition to voice calls.

The cellular phone illustrated in FIGS. 12A to 12C includes two housings1001 and 1002. The housing 1001 includes a display portion 1101, aspeaker 1102, a microphone 1103, operation keys 1104, a pointing device1105, a camera lens 1106, an external connection terminal 1107, and thelike, while the housing 1002 includes an earphone terminal 1008, akeyboard 1201, an external memory slot 1202, a camera lens 1203, a light1204, and the like. In addition, an antenna is incorporated in thehousing 1001.

In addition to the above structure, the cellular phone may incorporate anon-contact IC chip, a small-sized memory device, or the like.

In the display portion 1101, the light-emitting device described inEmbodiment 8 can be incorporated, and a display direction can be changedas appropriate depending on the usage mode. Since the cellular phone isprovided with the camera lens 1106 and the display portion 1101 on onesurface, the cellular phone can be used as a videophone. Further, astill image or a moving image can be taken with the camera lens 1203 andthe light 1204, using the display portion 1101 as a viewfinder. Thespeaker 1102 and the microphone 1103 can be used for video calls,recording, replaying, and the like without being limited to voice calls.With the use of the operation keys 1104, making and receiving calls,inputting simple information such as e-mail or the like, scrolling thescreen, moving the cursor, or the like are possible. Furthermore, thehousing 1001 and the housing 1002 which are overlapped with each other(FIG. 12A) can slide as illustrated in FIG. 12C, so that the cellularphone can be used as a portable information terminal. In this case,smooth operation can be conducted using the keyboard 1201 and thepointing device 1105. The external connection terminal 1107 can beconnected to an AC adaptor and various types of cables such as a USBcable, and charging, data communication with a computer, or the like arepossible. Furthermore, a large amount of data can be stored and moved byinserting a storage medium into the external memory slot 1202.

In addition to the above functions, the cellular phone may include aninfrared communication function, a television receiving function, or thelike.

FIG. 7 illustrates an audio replay device, specifically, a car audiosystem which includes a main body 701, a display portion 702, andoperation switches 703 and 704. The display portion 702 can be realizedwith the light-emitting device (passive matrix type or active matrixtype) of Embodiment 8. Further, this display portion 702 may be formedusing a segment type light-emitting device. In any case, by using alight-emitting element according to the present invention, a displayportion having a long lifetime can be formed with the use of a vehiclepower source (12 to 42 V). Furthermore, although Embodiment 9 describesan in-car audio system, a light-emitting device according to the presentinvention may also be used in a portable audio system or an audio systemfor home use.

FIG. 8 illustrates a digital player as an example of an audio replaydevice. The digital player illustrated in FIG. 8 includes a main body710, a display portion 711, a memory portion 712, an operation portion713, a pair of earphones 714, and the like. Note that a pair ofheadphones or wireless earphones can be used instead of the pair ofearphones 714. The display portion 711 can be formed by using thelight-emitting device (passive matrix type or active matrix type) ofEmbodiment 8. Further, the display portion 711 may be formed using asegment type light-emitting device. In any case, by using alight-emitting element according to the present invention, a displayportion that can display images even with the use of a secondary battery(e.g., a nickel-hydrogen battery) and has a long lifetime can beobtained. As the memory portion 712, a hard disk or a nonvolatile memoryis used. For example, by using a NAND-type nonvolatile memory with arecording capacity of 20 to 200 gigabytes (GB) and by operating theoperating portion 713, an image or a sound (music) can be recorded andreplayed. Note that in the display portion 702 and the display portion711, white characters are displayed against a black background, andaccordingly power consumption can be reduced. This is particularlyeffective for portable audio systems.

As described above, the applicable range of the light-emitting devicemanufactured according to the present invention is wide so that thelight-emitting device can be applied to electronic appliances in a widevariety of fields. By using any of the anthracene derivatives of thepresent invention, electronic appliances which have display portionswith a long lifetime can be provided. Further, electronic appliancesincluding a display portion having high color reproducibility can beprovided.

Further, the light-emitting device of the present invention can also beused as a lighting apparatus. An embodiment in which the light-emittingdevice of the present invention is used as a lighting apparatus isdescribed using FIG. 9.

FIG. 9 illustrates a liquid crystal display device using alight-emitting device according to the present invention as a backlight,as an example of the electronic appliance using a light-emitting deviceaccording to the present invention as a lighting apparatus. The liquidcrystal display device illustrated in FIG. 9 includes a housing 901, aliquid crystal layer 902, a backlight 903, and a housing 904, and theliquid crystal layer 902 is connected to a driver IC 905. Further, thelight-emitting device to which the present invention is applied is usedas the backlight 903, and a current is supplied through a terminal 906.

By using the light-emitting device of the present invention as thebacklight of a liquid crystal display device, a backlight with reducedpower consumption can be obtained. Further, since the light-emittingdevice of the present invention is a plane emission type lightingapparatus and can have a large area, the backlight can have a largearea, whereby a liquid crystal display device having a large area can beobtained. Furthermore, since the light-emitting device of the presentinvention is thin and has low power consumption, a thin shape and lowpower consumption of a display device can also be achieved. Moreover,since the light-emitting device of the present invention has a longlifetime, a liquid crystal display device using the light-emittingdevice of the present invention also has a long lifetime.

FIG. 10 illustrates an example in which a light-emitting device to whichthe present invention is applied is used as a desk lamp, which is alighting apparatus. The desk lamp illustrated in FIG. 10 includes ahousing 2001 and a light source 2002, and a light-emitting device of thepresent invention is used as the light source 2002. Since thelight-emitting device of the present invention has a long lifetime, thedesk lamp also has a long lifetime.

FIG. 11 illustrates an example in which the light-emitting device towhich the present invention is applied is used for an indoor lightingapparatus 3001. Since the light-emitting device of the present inventioncan have a large area, the light-emitting device of the presentinvention can be used as a lighting apparatus having a large emissionarea. Moreover, since the light-emitting device of the present inventionis thin and has a long lifetime, the light-emitting device can be usedfor a lighting apparatus that is thinned and has a longer lifetime. In aroom where the light-emitting device to which the present invention isthus applied is used as the indoor lighting apparatus 3001, a televisionset 3002 according to the present invention as described with referenceto FIG. 6A is placed, so that pubic broadcasting and movies can bewatched. In such a case, since each of the devices has a long lifetime,the frequency of replacing the lighting apparatus and the television setcan be reduced, whereby environmental load can be reduced.

Note that Embodiment 9 can be combined with any other embodiment asappropriate.

Example 1

In Example 1, a method of synthesizing3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation: 2PCzPA)represented by the structural formula (101), which is one of theanthracene derivatives of the present invention, is specificallydescribed.

[Step 1] Synthesis of 2-Bromo-9,10-diphenylanthracene (abbreviation: 2PAunit)(i) Synthesis of 2-Bromo-9,10-anthraquinone

A synthesis scheme of 2-bromo-9,10-anthraquinone is illustrated in(C-1).

In a IL three-neck flask were put 46 g (206 mmol) of copper(II) bromideand 500 mL of acetonitrile. To the mixture was added 17.3 g (168 mmol)of tert-butyl nitrite. This mixture was heated to 65° C. While themixture was heated, to this mixture was added 25 g (111 mmol) of2-amino-9,10-anthraquinone. This mixture was stirred at the sametemperature for 6 hours. Then, this solution was poured into about 500mL of hydrochloric acid (3 mol/L). This mixture was stirred for 3 hours.Then, the solid precipitated from the mixture was filtered off. Theobtained residue was washed with water and ethanol. Then, the residuewas dissolved in toluene, and this solution was suction filtered throughFlorisil (a product of Wako Pure Chemical Industries, Ltd., Catalog No.540-00135), Celite (a product of Wako Pure Chemical Industries, Ltd.,Catalog No. 531-16855), and alumina. The obtained filtrate wasconcentrated to give a solid. The solid was recrystallized withchloroform/hexane to give 2-bromo-9,10-anthracene, which was the objectof the synthesis, as 18.6 g of a light yellow powdered solid in a yieldof 58%.

(ii) Synthesis of 2-Bromo-9,10-dihydroanthracene-9,10-diol

A synthesis scheme of 2-bromo-9,10-dihydroanthracene-9,10-diol isillustrated in (C-2).

In a 300 mL three-neck flask was put 4.90 g (17.0 mmol) of2-bromo-9,10-anthraquinone, and the atmosphere in the flask was replacedwith nitrogen. To the flask was added 100 mL of tetrahydrofuran (THF),and 17.8 mL (37.3 mmol) of phenyllithium was dropped into this solution.After the completion of the dropping, this solution was stirred at roomtemperature for 15 hours. Then, this solution was washed with water, andthe aqueous layer was extracted with ethyl acetate. The extract solutionand the organic layer were combined and dried with magnesium sulfate.Then, this mixture was gravity filtered. The obtained filtrate wasconcentrated to give 2-bromo-9,10-dihydroanthracene-9,10-diol, which wasthe object of the synthesis.

(iii) Synthesis of 2-Bromo-9,10-diphenylanthracene.

A synthesis scheme of 2-bromo-9,10-diphenylanthracene is illustrated in(C-3).

In a 500 mL three-neck flask were put 7.55 g (17.0 mmol) of2-bromo-9,10-diphenylanthracene-9,10-diol, which was obtained, 5.06 g(30.5 mmol) of potassium iodide, 9.70 g (91.5 mmol) of sodiumphosphinate monohydrate, and 50 mL of glacial acetic acid, and thismixture was stirred at 120° C. for 2 hours. Then, to this mixture wasadded 30 mL of 50% phosphinic acid, and this mixture was further stirredat 120° C. for 1 hour. Then, this solution was washed with water, andthe aqueous layer was extracted with ethyl acetate. The extract solutionand the organic layer were combined and dried with magnesium sulfate.This mixture was gravity filtered. The obtained filtrate wasconcentrated to give a light yellow solid. The obtained solid wasdissolved in toluene, and this solution was suction filtered throughCelite (a product of Wako Pure Chemical Industries, Ltd., Catalog No.531-16855), Florisil (a product of Wako Pure Chemical Industries, Ltd.,Catalog No. 540-00135), and alumina. The obtained filtrate wasconcentrated to give a solid. The solid was recrystallized withchloroform/hexane to give the object of the synthesis as 5.1 g of alight yellow powdered solid in a yield of 74% (which is the yield of theschemes (C-2) and (C-3)).

[Step 2] Synthesis of 2PCzPA

A synthesis scheme of 2PCzPA is illustrated in (C-4).

In a 100 mL three neck flask were put 1.5 g (3.7 mmol) of2-bromo-9,10-diphenylanthracene, 1.1 g (3.7 mmol) of4-(9H-carbazol-9-yl)phenylboronic acid, and 0.16 g (0.50 mmol) oftri(ortho-tolyl)phosphine, and the atmosphere in the flask was replacedwith nitrogen. To this mixture were added 20 mL of toluene, 10 mL ofethanol, and 13 mL of an aqueous potassium carbonate solution (2.0mol/L). This mixture was deaerated while being stirred under reducedpressure. Then, the atmosphere in the flask was replaced with nitrogen.To this mixture was added 28 mg (0.10 mmol) of palladium(II) acetate.This mixture was refluxed at 110° C. for 12 hours. Then, after thismixture was cooled to room temperature, about 20 mL of toluene was addedthereto, and the mixture was filtered through Celite (a product of WakoPure Chemical Industries, Ltd., Catalog No. 531-16855). The organiclayer of the obtained mixture was washed with water and a saturatedsaline solution, and dried with magnesium sulfate. This mixture wasgravity filtered. The obtained filtrate was concentrated to give a brownoily substance. This oily substance was purified by silica gel columnchromatography (a developing solvent was a mixture of hexane and toluenein a ratio of 7:3). The obtained light yellow solid was recrystallizedwith ethanol to give 1.2 g of a light yellow powdered solid in a yieldof 58%.

Then, 1.2 g of the obtained light-yellow powdered solid was sublimatedand purified by train sublimation. For sublimation purificationconditions, 2PCzPA was heated at 280° C. under a pressure of 8.7 Pa withargon gas at a flow rate of 3.0 mL/min. After the sublimationpurification, 2PCzPA was recovered as 0.83 g of a light yellow solid ina yield of 74%.

By nuclear magnetic resonance (NMR) measurement, it was confirmed thatthis compound was 3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole(abbreviation: 2PCzPA).

The ¹H NMR data of 2PCzPA are shown as follows: ¹H NMR (CDCl₃, 300 MHz):δ=7.30-7.34 (m, 3H), 7.41-7.49 (m, 4H), 7.53-7.65 (m, 15H), 7.70-7.74(m, 2H), 7.79-7.84 (m, 2H), 7.98 (s, 1H), 8.15 (d, J=7.8 Hz, 1H), 8.31(d, J=2.1 Hz, 1H). Further, FIGS. 13A and 13B show ¹H NMR charts. Notethat FIG. 13B is a chart in which the range of 7.0 to 8.5 ppm in FIG.13A is enlarged.

Further, the decomposition temperature of 2PCzPA, which was obtained,was measured with a high vacuum differential type differential thermalbalance (TG-DTA2410SA, a product of Bruker AXS K.K.). The temperatureincrease rate was set to 10° C./min, and the temperature was increasedunder normal pressure. Accordingly, a reduction in weight by 5% was seenat 416° C. Thus, 2PCzPA was found to have high thermal stability.

Further, FIG. 14 shows an absorption spectrum of a toluene solution of2PCzPA, and FIG. 15 shows an emission spectrum of the toluene solutionof 2PCzPA. An ultraviolet-visible spectrophotometer (V-550, a product ofJASCO Corporation) was used for the measurement. The measurement wasconducted with the solution put in the quartz cell. The absorptionspectrum from which the absorption spectrum obtained with only tolueneput in the quartz cell was subtracted is shown. In FIG. 14, thehorizontal axis represents wavelength (nm) and the vertical axisrepresents absorption intensity (given (arbitrary) unit). In FIG. 15,the horizontal axis represents wavelength (nm) and the vertical axisrepresents emission intensity (given unit). With the toluene solution,absorption was observed at around 302 nm, 331 nm, 366 nm, 386 nm, and409 nm. In addition, with the toluene solution, the peak emissionwavelengths were around 436 nm and 459 nm (excitation wavelength of 370nm).

Further, FIG. 16 shows an absorption spectrum of a thin film of 2PCzPA,and FIG. 17 shows an emission spectrum of the thin film of 2PCzPA. Anultraviolet-visible spectrophotometer (V-550, a product of JASCOCorporation) was used for the measurement. A sample was prepared byevaporation on a quartz substrate, and the absorption spectrum fromwhich the absorption spectrum of quartz is subtracted is shown. In FIG.16, the horizontal axis represents wavelength (nm) and the vertical axisrepresents absorption intensity (given unit). In FIG. 17, the horizontalaxis represents wavelength (nm) and the vertical axis representsemission intensity (given unit). With the thin film, absorption wasobserved at around 283 nm, 305 nm, 340 nm, 395 nm, and 423 nm. Inaddition, with the thin film, the peak emission wavelengths were around456 nm and 476 nm (excitation wavelength of 418 nm).

Further, by measurement with a photoelectron spectrometer (AC-2, aproduct of Riken Keiki, Co., Ltd.) in the atmosphere, the ionizationpotential of the thin film of 2PCzPA was found to be 5.49 eV.Accordingly, it was understood that the HOMO level was −5.49 eV.Furthermore, with the use of the absorption spectrum data of the thinfilm of 2PCzPA, the absorption edge was obtained by a Tauc plot assumingdirect 5 transition. The absorption edge was estimated as an opticalenergy gap, whereby the energy gap was 2.77 eV. From the obtained valuesof the energy gap and HOMO level, the LUMO level was −2.72 eV.

Further, the oxidation-reduction characteristics of 2PCzPA were measuredby cyclic voltammetry (CV). Note that an electrochemical analyzer (ALSmodel 600A, a product of BAS Inc.) was used for the measurement.

For a solution used in the CV measurement, dehydrated dimethylformamide(DMF, a product of Sigma-Aldrich Inc., 99.8%, Catalog No. 22705-6) wasused as a solvent, and tetra-n-butylammonium perchlorate (n-Bu₄NClO₄, aproduct of Tokyo Chemical Industry Co., Ltd., Catalog No. T0836), whichserves as a supporting electrolyte, was dissolved in the solvent suchthat the concentration of tetra-n-butylammonium perchlorate was 100mmol/L. Furthermore, 2PCzPA, which was the object of the measurement,was dissolved in the solution such that the concentration of 2PCzPA was2 mmol/L. In addition, a platinum electrode (PTE platinum electrode, aproduct of BAS Inc.) was used as a working electrode, a platinumelectrode (Pt counter electrode for VC-3, (5 cm), a product of BAS Inc.)was used as an auxiliary electrode, and an Ag/Ag⁺ electrode (RE5reference electrode for nonaqueous solvent, a product of BAS Inc.,) wasused as a reference electrode. Note that the measurement was conductedat room temperature.

The oxidation characteristics of 2PCzPA were examined as follows. A scanfor changing the potential of the working electrode with respect to thereference electrode from −0.16 V to 1.30 V and then from 1.30 V to −0.16V was set to one cycle, and the measurement was performed for 100cycles. Further, the reduction characteristics of 2PCzPA were examinedas follows. A scan for changing the potential of the working electrodewith respect to the reference electrode from −1.02 V to −2.54 V and thenfrom −2.54 V to −1.02 V was set to one cycle, and the measurement wasperformed for 100 cycles. Note that the scan rate for the CV measurementwas set to 0.1 V/s.

FIG. 18 shows CV measurement results of the oxidation characteristics of2PCzPA. FIG. 19 shows CV measurement results of the reductioncharacteristics of 2PCzPA. In each of FIG. 18 and FIG. 19, thehorizontal axis represents potential (V) of the working electrode withrespect to the reference electrode, and the vertical axis represents theamount of current (μA) flowing between the working electrode and theauxiliary electrode. From FIG. 18, current exhibiting oxidation wasobserved at around 0.79 V (vs. the Ag/Ag⁺ electrode). Further, from FIG.19, current exhibiting reduction was observed at around −2.24 V (vs. theAg/Ag⁺ electrode).

Although the scan was repeated for as many as 100 cycles, significantchanges in the peak position and peak intensity of the CV curves werenot observed in each of the oxidation reactions and reduction reactions.This shows that the anthracene derivative of the present invention issignificantly stable against repetition of oxidation reactions andreduction reactions.

Example 2

In Example 2, a method of synthesizing9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which is one of theanthracene derivatives of the present invention, is specificallydescribed.

[Step 1] Synthesis of 9-[4-(9,10-Diphenyl-2-anthryl)phenyl]-9H-carbazole(abbreviation: 2CzPPA)

A synthesis scheme of 2CzPPA is illustrated in (D-1).

In a 100 mL three neck flask were put 2.0 g (4.9 mmol) of2-bromo-9,10-diphenylanthracene, 1.4 g (4.9 mmol) of4-(9H-carbazol-9-yl)phenylboronic acid, and 0.15 g (0.50 mmol) oftri(ortho-tolyl)phosphine, and the atmosphere in the flask was replacedwith nitrogen. To this mixture were added 15 mL of toluene, 15 mL ofethanol, and 10 mL of an aqueous potassium carbonate solution (2.0mol/L). This mixture was deaerated while being stirred under reducedpressure. Then, the atmosphere in the flask was replaced with nitrogen.To this mixture was added 23 mg (0.10 mmol) of palladium(II) acetate.This mixture was refluxed at 100° C. for 20 hours. Then, after thismixture was cooled to room temperature, about 50 mL of toluene was addedthereto, and the mixture was filtered through a filter paper. Theobtained mixture was washed with water, and the aqueous layer wasextracted with toluene. The extract solution and the organic layer werecombined and washed with a saturated saline solution, and the organiclayer was dried with magnesium sulfate. This mixture was gravityfiltered. The obtained filtrate was concentrated to give a light yellowsolid. This solid was washed with toluene to give the object of thesynthesis as 1.5 g of a light yellow powdered solid in a yield of 54%.

Then, 1.5 g of the obtained light-yellow powdered solid was sublimatedand purified by train sublimation. For sublimation purificationconditions, 2CzPPA was heated at 260° C. with argon gas at a flow rateof 3.0 mL/min. After the sublimation purification, 2CzPPA was recoveredas 1.4 g of a light yellow solid in a yield of 94%.

By nuclear magnetic resonance (NMR) measurement, it was confirmed thatthis compound was 9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole(abbreviation: 2CzPPA).

The ¹H NMR data of 2CzPPA are shown as follows: ¹H NMR (CDCl₃, 300 MHz):δ=7.30 (d, J=6.3 Hz, 2H), 7.33-7.75 (m, 21H), 7.77 (d, J=8.1 Hz, 2H),7.85 (d, J=9.0 Hz, 1H), 8.01 (d, J=2.1 Hz, 1H), 8.15 (d, J=7.8 Hz, 2H).Further, FIGS. 20A and 20B show ¹H NMR charts. Note that FIG. 20B is achart in which the range of 7.0 to 8.5 ppm in FIG. 20A is enlarged.

Further, the decomposition temperature of 2CzPPA, which was obtained,was measured with a high vacuum differential type differential thermalbalance (TG-DTA2410SA, a product of Bruker AXS K.K.). The temperatureincrease rate was set to 10° C./min, and the temperature was increasedunder normal pressure. Accordingly, a reduction in weight by 5% was seenat 421° C. Thus, 2CzPPA was found to have high thermal stability.

Further, FIG. 21 shows an absorption spectrum of a toluene solution of2CzPPA, and FIG. 22 shows an emission spectrum of the toluene solutionof 2CzPPA. An ultraviolet-visible spectrophotometer (V-550, a product ofJASCO Corporation) was used for the measurement. The measurement wasconducted with the solution put in the quartz cell. The absorptionspectrum from which the absorption spectrum obtained with only tolueneput in the quartz cell was subtracted is shown. In FIG. 21, thehorizontal axis represents wavelength (nm) and the vertical axisrepresents absorption intensity (given unit). In FIG. 22, the horizontalaxis represents wavelength (nm) and the vertical axis representsemission intensity (given unit). With the toluene solution, absorptionwas observed at around 282 nm, 337 nm, 366 nm, 385 nm, and 407 nm. Inaddition, with the toluene solution, the peak emission wavelengths were426 nm and 451 nm (excitation wavelength of 370 nm).

Further, FIG. 23 shows an absorption spectrum of a toluene solution of2CzPPA, and FIG. 24 shows an emission spectrum of the toluene solutionof 2CzPPA. An ultraviolet-visible spectrophotometer (V-550, a product ofJASCO Corporation) was used for the measurement. A sample was preparedby evaporation on a quartz substrate, and the absorption spectrum fromwhich the absorption spectrum of quartz is subtracted is shown. In FIG.23, the horizontal axis represents wavelength (nm) and the vertical axisrepresents absorption intensity (given unit). In FIG. 24, the horizontalaxis represents wavelength (nm) and the vertical axis representsemission intensity (given unit). With the thin film, absorption wasobserved at around 240 nm, 290 nm, 344 nm, 393 nm, and 415 nm. Inaddition, with the thin film, the peak emission wavelength was 461 nm(excitation wavelength of 341 nm).

Further, by measurement with a photoelectron spectrometer (AC-2, aproduct of Riken Keiki, Co., Ltd.) in the atmosphere, the ionizationpotential of the thin film of 2CzPPA was found to be 5.72 eV As aresult, it was understood that the HOMO level was −5.72 eV. Furthermore,with the use of the absorption spectrum data of the thin film of 2CzPPA,the absorption edge was obtained by a Tauc plot assuming directtransition. The absorption edge was estimated as an optical energy gap,whereby the energy gap was 2.84 eV. From the obtained values of theenergy gap and HOMO level, the LUMO level was −2.88 eV.

Further, the oxidation-reduction characteristics of 2CzPPA were measuredby cyclic voltammetry (CV). Note that an electrochemical analyzer (ALSmodel 600A, a product of BAS Inc.) was used for the measurement.

For a solution used in the CV measurement, dehydrated dimethylformamide(DMF, a product of Sigma-Aldrich Inc., 99.8%, Catalog No. 22705-6) wasused as a solvent, and tetra-n-butylammonium perchlorate (n-Bu₄NClO₄, aproduct of Tokyo Chemical Industry Co., Ltd., Catalog No. T0836), whichwas a supporting electrolyte, was dissolved in the solvent such that theconcentration of tetra-n-butylammonium perchlorate was 100 mmol/L.Furthermore, 2CzPPA, which was the object of the measurement, wasdissolved in the solution such that the concentration of 2CzPPA was 2mmol/L. In addition, a platinum electrode (PTE platinum electrode, aproduct of BAS Inc.) was used as a working electrode, a platinumelectrode (Pt counter electrode for VC-3, (5 cm), a product of BAS Inc.)was used as an auxiliary electrode, and an Ag/Ag⁺ electrode (RE5reference electrode for nonaqueous solvent, a product of BAS Inc.,) wasused as a reference electrode. Note that the measurement was conductedat room temperature.

The oxidation characteristics of 2CzPPA were examined as follows. A scanfor changing the potential of the working electrode with respect to thereference electrode from −0.03 V to 1.30 V and then from 1.30 V to −0.03V was set to one cycle, and the measurement was performed for 100cycles. Further, the reduction characteristics of 2CzPPA were examinedas follows. A scan for changing the potential of the working electrodewith respect to the reference electrode from −1.08 V to −2.50 V and thenfrom −2.50 V to −1.08 V was set to one cycle, and the measurement wasperformed for 100 cycles. Note that the scan rate for the CV measurementwas set to 0.1 V/s.

FIG. 25 shows CV measurement results of the oxidation characteristics of2CzPPA. FIG. 26 shows CV measurement results of the reductioncharacteristics of 2CzPPA. In each of FIG. 25 and FIG. 26, thehorizontal axis represents potential (V) of the working electrode withrespect to the reference electrode, and the vertical axis represents theamount of current (μA) flowing between the working electrode and theauxiliary electrode. From FIG. 25, current exhibiting oxidation wasobserved at around 0.89 V (vs. the Ag/Ag⁺ electrode). Further, from FIG.26, current exhibiting reduction was observed at around −2.17 V (vs. theAg/Ag⁺ electrode).

Although the scan was repeated for as many as 100 cycles, significantchanges in the peak position and peak intensity of the CV curves werenot observed in each of the oxidation reactions and reduction reactions.This shows that the anthracene derivative of the present invention issignificantly stable against repetition of oxidation reactions andreduction reactions.

Example 3

In Example 3, light-emitting elements of the present invention will bedescribed using FIG. 27. Structural formulae of materials used inExample 3 are illustrated below.

Hereinafter, a method of fabricating light-emitting elements of Example3 is described.

(Light-Emitting Element 1)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed on a glass substrate 2101 by a sputtering method, whereby a firstelectrode 2102 was formed. Note that the thickness of the firstelectrode 2102 was set to 110 nm and the area of the electrode was setto 2 mm×2 mm.

Next, the substrate provided with the first electrode was fixed to asubstrate holder provided in a vacuum evaporation apparatus such thatthe surface on which the first electrode 2102 was formed faced downward.After the pressure in a film formation chamber was reduced toapproximately 10⁻⁴ Pa, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(abbreviation: NPB) and molybdenum(VI) oxide were co-evaporated on thefirst electrode 2102, whereby a layer 2111 including a compositematerial of an organic compound and an inorganic compound was formed.The thickness of the layer 2111 was set to 50 nm and the mass ratio ofNPB to molybdenum(VI) oxide was adjusted so as to be 4:1(=NPB:molybdenum oxide). Note that a co-evaporation method refers to anevaporation method by which evaporation is conducted from a plurality ofevaporation sources at the same time in one treatment chamber.

Next, a 10-nm-thick film of4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) wasformed on the layer 2111 including a composite material by anevaporation method with resistance heating, whereby a hole-transportinglayer 2112 was formed.

Furthermore, 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: CzPA) and3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole (abbreviation: 2PCzPA)represented by the structural formula (101), which was one of theanthracene derivatives of the present invention, were co-evaporated onthe hole-transporting layer 2112, whereby a 30-nm-thick light-emittinglayer 2113 was formed. Here, the mass ratio of CzPA to 2PCzPA wasadjusted to be 1:0.1 (=CzPA:2PCzPA).

Then, a 10-nm-thick film of tris(8-quinolinolato)aluminum(III)(abbreviation: Alq) was formed on the light-emitting layer 2113 by anevaporation method with resistance heating, whereby anelectron-transporting layer 2114 was formed.

Furthermore, tris(8-quinolinolato)aluminum(II) (abbreviation: Alq) andlithium (Li) were co-evaporated on the electron-transporting layer 2114,whereby a 20-nm-thick electron-injecting layer 2115 was formed. Here,the mass ratio of Alq to Li was adjusted to be 1:0.01 (=Alq:Li).

Lastly, a 200-nm-thick aluminum film was formed on theelectron-injecting layer 2115 by an evaporation method with resistanceheating, whereby a second electrode 2104 was formed. Thus, alight-emitting element 1 was fabricated.

(Light-Emitting Element 2)

A light-emitting element 2 was fabricated in a manner similar to that ofthe light-emitting element 1 by using the same kind of substrate as thelight-emitting element 1 and9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was one ofthe anthracene derivatives of the present invention, instead of 2PCzPA.That is, by co-evaporation of9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA) and9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was theanthracene derivative of the present invention, the 30-nm-thicklight-emitting layer 2113 was formed on the hole-transporting layer2112. Here, the mass ratio of CzPA to 2CzPPA was adjusted to be 1:0.1(=CzPA:2CzPPA). The layers other than the light-emitting layer 2113 wereformed in a manner similar to those of the light-emitting element 1.

The thus obtained light-emitting elements 1 and 2 were sealed in a glovebox containing a nitrogen atmosphere so as not to be exposed to air.Then, operation characteristics of these light-emitting elements weremeasured. Note that the measurement was carried out at room temperature(in the atmosphere kept at 25° C.).

FIG. 28 shows the current density vs. luminance characteristics of thelight-emitting elements 1 and 2. FIG. 29 shows the voltage vs. luminancecharacteristics of the light-emitting elements 1 and 2. FIG. 30 showsthe luminance vs. current efficiency characteristics of thelight-emitting elements 1 and 2. FIG. 31 shows the voltage vs. currentcharacteristics of the light-emitting elements 1 and 2.

Further, FIG. 32 shows the emission spectra of the light-emittingelements 1 and 2 at a current of 1 mA. As apparent from FIG. 32, lightemission from the light-emitting element 1 was from 2PCzPA. Further,light emission from the light-emitting element 2 was from 2CzPPA.

The CIE chromaticity coordinates of the light-emitting element 1 at aluminance of 800 cd/m² were (x=0.16, y=0.13), and blue light emissionwith high color purity was exhibited. Further, at a luminance of 800cd/m², the current efficiency of the light-emitting element 1 was 2.0cd/A, and the external quantum efficiency thereof was 1.8%. Furthermore,at a luminance of 800 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 1 were 6.6 V, 39.5 mA/cm², and1.0 lm/W, respectively.

The CIE chromaticity coordinates of the light-emitting element 2 at aluminance of 990 cd/m² were (x=0.16, y=0.11), and blue light emissionwith high color purity was exhibited. Further, at a luminance of 990cd/m², the current efficiency of the light-emitting element 2 was 1.5cd/A, and the external quantum efficiency thereof was 1.4%. Furthermore,at a luminance of 990 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 2 were 6.8 V, 67.3 mA/cm², and0.68 lm/W, respectively.

Thus, the light-emitting element 1 and the light-emitting element 2 eachemit blue light with high color purity. Therefore, by using theanthracene derivative of the present invention as a light-emittingsubstance of a light-emitting layer, a light-emitting element that emitsblue light with high color purity can be obtained.

Example 4

In Example 4, light-emitting elements of the present invention will bedescribed using FIG. 27. Structural formulae of materials used inExample 4 are illustrated below. Note that the structural formulae ofthe materials which have already been illustrated are omitted.

Hereinafter, a method of fabricating light-emitting elements of Example4 is described.

(Light-Emitting Element 3)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed on the glass substrate 2101 by a sputtering method, whereby thefirst electrode 2102 was formed. Note that the thickness of the firstelectrode 2102 was set to 110 nm and the area of the electrode was setto 2 mm×2 mm.

Next, the substrate provided with the first electrode was fixed to asubstrate holder provided in a vacuum evaporation apparatus such thatthe surface on which the first electrode 2102 was formed faced downward.After the pressure in a film formation chamber was reduced toapproximately 10⁻⁴ Pa, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(abbreviation: NPB) and molybdenum(VI) oxide were co-evaporated on thefirst electrode 2102, whereby the layer 2111 including a compositematerial of an organic compound and an inorganic compound was formed.The thickness of the layer 2111 was set to 50 nm and the mass ratio ofNPB to molybdenum(VI) oxide was adjusted so as to be 4:1(=NPB:molybdenum oxide). Note that a co-evaporation method refers to anevaporation method by which evaporation is conducted from a plurality ofevaporation sources at the same time in one treatment chamber.

Next, a 10-nm-thick film of4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) wasformed on the layer 2111 including a composite material by anevaporation method with resistance heating, whereby thehole-transporting layer 2112 was formed.

Furthermore, 3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole(abbreviation: 2PCzPA) represented by the structural formula (101),which was one of the anthracene derivatives of the present invention,and N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA) were co-evaporated on the hole-transporting layer2112, whereby the 40-nm-thick light-emitting layer 2113 was formed.Here, the mass ratio of 2PCzPA to 2PCAPA was adjusted to be 1:0.05(=2PCzPA:2PCAPA).

Then, a 30-nm-thick film of tris(8-quinolinolato)aluminum(III)(abbreviation: Alq) was formed on the light-emitting layer 2113 by anevaporation method with resistance heating, whereby theelectron-transporting layer 2114 was formed.

Furthermore, a 1-nm-thick lithium fluoride film was formed on theelectron-transporting layer 2114 by an evaporation method withresistance heating, whereby the electron-injecting layer 2115 wasformed.

Lastly, a 200-nm-thick aluminum film was formed on theelectron-injecting layer 2115 by an evaporation method with resistanceheating, whereby the second electrode 2104 was formed. Thus, alight-emitting element 3 was fabricated.

(Light-Emitting Element 4)

A light-emitting element 4 was fabricated in a manner similar to that ofthe light-emitting element 3 by using the same kind of substrate as thelight-emitting element 3 and9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was one ofthe anthracene derivatives of the present invention, instead of 2PCzPA.That is, by co-evaporation of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was theanthracene derivative of the present invention, andN-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA), the 40-nm-thick light-emitting layer 2113 wasformed on the hole-transporting layer 2112. Here, the mass ratio of2CzPPA to 2PCAPA was adjusted to be 1:0.05 (=2CzPPA:2PCAPA). The layersother than the light-emitting layer 2113 were formed in a manner similarto those of the light-emitting element 3.

The thus obtained light-emitting elements 3 and 4 were sealed in a glovebox containing a nitrogen atmosphere so as not to be exposed to air.Then, operation characteristics of these light-emitting elements weremeasured. Note that the measurement was carried out at room temperature(in the atmosphere kept at 25° C.).

FIG. 33 shows the current density vs. luminance characteristics of thelight-emitting elements 3 and 4. FIG. 34 shows the voltage vs. luminancecharacteristics of the light-emitting elements 3 and 4. FIG. 35 showsthe luminance vs. current efficiency characteristics of thelight-emitting elements 3 and 4. FIG. 36 shows the voltage vs. currentcharacteristics of the light-emitting elements 3 and 4.

Further, FIG. 37 shows the emission spectra of the light-emittingelements 3 and 4 at a current of 1 mA. As apparent from FIG. 37, lightemission from each of the light-emitting elements 3 and 4 were from2PCAPA.

The CIE chromaticity coordinates of the light-emitting element 3 at aluminance of 3400 cd/m² were (x=0.30, y=0.62), and green light emissionwas exhibited. Further, at a luminance of 3400 cd/m², the currentefficiency of the light-emitting element 3 was 14.2 cd/A. Furthermore,at a luminance of 3400 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 3 were 6.0 V, 24.0 mA/cm², and7.4 lm/W, respectively.

The CIE chromaticity coordinates of the light-emitting element 4 at aluminance of 2800 cd/m² were (x, y)=(0.29, 0.62), and green lightemission was exhibited. Further, at a luminance of 2800 cd/m², thecurrent efficiency of the light-emitting element 4 was 13.2 cd/A.Furthermore, at a luminance of 2800 cd/m², the voltage, current density,and power efficiency of the light-emitting element 4 were 6.8 V, 21.0mA/cm², and 6.1 lm/W, respectively.

Further, FIG. 38 shows the results of continuous lighting tests in whichthe light-emitting elements 3 and 4 were continuously lit by constantcurrent driving with the initial luminance thereof set to 3000 cd/m²(the vertical axis represents normalized luminance on condition that3000 cd/m² was 100%). As can be seen from FIG. 38, the light-emittingelements 3 and 4 kept 85% and 82% of the initial luminance,respectively, after 710 hours. Therefore, it is understood that thelight-emitting elements of the present invention have a long lifetime.

Thus, by using any of the anthracene derivatives of the presentinvention as a host material of the light-emitting layer, alight-emitting element with a long lifetime can be obtained.

Example 5

In Example 5, light-emitting elements of the present invention will bedescribed using FIG. 27. Structural formulae of materials used inExample 5 are illustrated below. Note that the structural formulae ofthe materials which have already been illustrated are omitted.

Hereinafter, a method of fabricating light-emitting elements of Example5 is described.

(Light-Emitting Element 5)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed on a glass substrate 2101 by a sputtering method, whereby a firstelectrode 2102 was formed. Note that the thickness of the firstelectrode 2102 was set to 110 nm and the area of the electrode was setto 2 mm×2 mm.

Next, the substrate provided with the first electrode was fixed to asubstrate holder provided in a vacuum evaporation apparatus such thatthe surface on which the first electrode 2102 was formed faced downward.After the pressure in a film formation chamber was reduced toapproximately 10⁻⁴ Pa, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(abbreviation: NPB) and molybdenum(VI) oxide were co-evaporated on thefirst electrode 2102, whereby a layer 2111 including a compositematerial of an organic compound and an inorganic compound was formed.The thickness of the layer 2111 was set to 50 nm and the mass ratio ofNPB to molybdenum(VI) oxide was adjusted so as to be 4:1(=NPB:molybdenum oxide). Note that a co-evaporation method refers to anevaporation method by which evaporation is conducted from a plurality ofevaporation sources at the same time in one treatment chamber.

Next, a 10-nm-thick film of4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) wasformed on the layer 2111 including a composite material by anevaporation method with resistance heating, whereby thehole-transporting layer 2112 was formed.

Furthermore, 3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole(abbreviation: 2PCzPA) represented by the structural formula (101),which was one of the anthracene derivatives of the present invention,and N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA) were co-evaporated on the hole-transporting layer2112, whereby the 40-nm-thick light-emitting layer 2113 was formed.Here, the mass ratio of 2PCzPA to 2PCAPA was adjusted to be 1:0.05(=2PCzPA:2PCAPA).

Then, a 30-nm-thick film of bathophenanthroline (abbreviation: BPhen)was formed on the light-emitting layer 2113 by an evaporation methodwith resistance heating, whereby the electron-transporting layer 2114was formed.

Then, a 1-nm-thick lithium fluoride film was formed on theelectron-transporting layer 2114 by an evaporation method withresistance heating, whereby the electron-injecting layer 2115 wasformed.

Lastly, a 200-nm-thick aluminum film was formed on theelectron-injecting layer 2115 by an evaporation method with resistanceheating, whereby the second electrode 2104 was formed. Thus, alight-emitting element 5 was fabricated.

(Light-Emitting Element 6)

A light-emitting element 6 was fabricated in a manner similar to that ofthe light-emitting element 5 by using the same kind of substrate as thelight-emitting element 5 and9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was one ofthe anthracene derivatives of the present invention, instead of 2PCzPA.That is, by co-evaporation of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was theanthracene derivative of the present invention, andN-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA), the 40-nm-thick light-emitting layer 2113 wasformed on the hole-transporting layer 2112. Here, the mass ratio of2CzPPA to 2PCAPA was adjusted to be 1:0.05 (=2CzPPA:2PCAPA). The layersother than the light-emitting layer 2113 were formed in a manner similarto those of the light-emitting element 5.

The thus obtained light-emitting elements 5 and 6 were sealed in a glovebox containing a nitrogen atmosphere so as not to be exposed to air.Then, operation characteristics of these light-emitting elements weremeasured. Note that the measurement was carried out at room temperature(in the atmosphere kept at 25° C.).

FIG. 39 shows the current density vs. luminance characteristics of thelight-emitting elements 5 and 6. FIG. 40 shows the voltage vs. luminancecharacteristics of the light-emitting elements 5 and 6. FIG. 41 showsthe luminance vs. current efficiency characteristics of thelight-emitting elements 5 and 6. FIG. 42 shows the voltage vs. currentcharacteristics of the light-emitting elements 5 and 6.

Further, FIG. 43 shows the emission spectra of the light-emittingelements 5 and 6 at a current of 1 mA. As apparent from FIG. 43, lightemission from each of the light-emitting elements 5 and 6 were from2PCAPA.

The CIE chromaticity coordinates of the light-emitting element 5 at aluminance of 3500 cd/m² were (x=0.28, y=0.61), and green light emissionwas exhibited. Further, at a luminance of 3500 cd/m², the currentefficiency of the light-emitting element 5 was 13.1 cd/A. Furthermore,at a luminance of 3500 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 5 were 3.2 V, 26.3 mA/cm², and12.9 lm/W, respectively.

The CIE chromaticity coordinates of the light-emitting element 6 at aluminance of 3500 cd/m² were (x=0.28, y=0.61), and green light emissionwas exhibited. Further, at a luminance of 3500 cd/m², the currentefficiency of the light-emitting element 6 was 10.1 cd/A. Furthermore,at a luminance of 3500 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 6 were 3.0 V, 35.0 mA/cm², and10.5 lm/W, respectively.

Further, FIG. 44 shows the results of continuous lighting tests in whichthe light-emitting elements 5 and 6 were continuously lit by constantcurrent driving with the initial luminance thereof set to 3000 cd/m²(the vertical axis represents normalized luminance on condition that3000 cd/m² was 100%). As can be seen from FIG. 44, the light-emittingelements 5 and 6 kept 81% and 84% of the initial luminance,respectively, after 140 hours. Therefore, it is understood that thelight-emitting elements of the present invention have a long lifetime.

Thus, by using any of the anthracene derivatives of the presentinvention as a host material of the light-emitting layer, alight-emitting element with a long lifetime can be obtained.

Example 6

In Example 6, light-emitting elements of the present invention will bedescribed using FIG. 45. Structural formulae of materials used inExample 6 are illustrated below. Note that the structural formulae ofthe materials which have already been illustrated are omitted.

Hereinafter, a method of fabricating light-emitting elements of Example6 is described.

(Light-Emitting Element 7)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed on the glass substrate 2101 by a sputtering method, whereby thefirst electrode 2102 was formed. Note that the thickness of the firstelectrode 2102 was set to 110 nm and the area of the electrode was setto 2 mm×2 mm.

Next, the substrate provided with the first electrode was fixed to asubstrate holder provided in a vacuum evaporation apparatus such thatthe surface on which the first electrode 2102 was formed faced downward.After the pressure in a film formation chamber was reduced toapproximately 10⁻⁴ Pa, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(abbreviation: NPB) and molybdenum(VI) oxide were co-evaporated on thefirst electrode 2102, whereby the layer 2111 including a compositematerial of an organic compound and an inorganic compound was formed.The thickness of the layer 2111 was set to 50 nm and the mass ratio ofNPB to molybdenum(VI) oxide was adjusted so as to be 4:1(=NPB:molybdenum oxide). Note that a co-evaporation method refers to anevaporation method by which evaporation is conducted from a plurality ofevaporation sources at the same time in one treatment chamber.

Next, a 10-nm-thick film of4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) wasformed on the layer 2111 including a composite material by anevaporation method with resistance heating, whereby thehole-transporting layer 2112 was formed.

Furthermore, 3-(9,10-diphenyl-2-anthryl)-9-phenyl-9H-carbazole(abbreviation: 2PCzPA) represented by the structural formula (101),which was one of the anthracene derivatives of the present invention,and N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA) were co-evaporated on the hole-transporting layer2112, whereby the 30-nm-thick light-emitting layer 2113 was formed.Here, the mass ratio of 2PCzPA to 2PCAPA was adjusted to be 1:0.05(=2PCzPA:2PCAPA).

Furthermore, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq) andN,N′-diphenylquinacridon (abbreviation: DPQd) were co-evaporated on thelight-emitting layer 2113, whereby a 10 nm-thick functional layer 2116for controlling transport of electrons was formed. Here, the mass ratioof Alq to DPQd was adjusted to be 1:0.005 (=Alq:DPQd).

Then, a 30-nm-thick bathophenanthroline (abbreviation: BPhen) film wasformed on the functional layer 2116 by an evaporation method withresistance heating, whereby the electron-transporting layer 2114 wasformed.

Furthermore, a 1-nm-thick lithium fluoride film was formed on theelectron-transporting layer 2114, whereby the electron-injecting layer2115 was formed.

Lastly, a 200-nm-thick aluminum film was formed on theelectron-injecting layer 2115 by an evaporation method with resistanceheating, whereby the second electrode 2104 was formed. Thus, alight-emitting element 7 was fabricated.

(Light-Emitting Element 8)

A light-emitting element 8 was fabricated in a manner similar to that ofthe light-emitting element 7 by using the same kind of substrate as thelight-emitting element 7 and9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was one ofthe anthracene derivatives of the present invention, instead of 2PCzPA.That is, by co-evaporation of9-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole (abbreviation:2CzPPA) represented by the structural formula (201), which was theanthracene derivative of the present invention, andN-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA), the 30-nm-thick light-emitting layer 2113 wasformed on the hole-transporting layer 2112. Here, the mass ratio of2CzPPA to 2PCAPA was adjusted to be 1:0.05 (=2CzPPA:2PCAPA). The layersother than the light-emitting layer 2113 were formed in a manner similarto those of the light-emitting element 7.

The thus obtained light-emitting elements 7 and 8 were sealed in a glovebox containing a nitrogen atmosphere so as not to be exposed to air.Then, operation characteristics of these light-emitting elements weremeasured. Note that the measurement was carried out at room temperature(in the atmosphere kept at 25° C.).

FIG. 46 shows the current density vs. luminance characteristics of thelight-emitting elements 7 and 8. FIG. 47 shows the voltage vs. luminancecharacteristics of the light-emitting elements 7 and 8. FIG. 48 showsthe luminance vs. current efficiency characteristics of thelight-emitting elements 7 and 8. FIG. 49 shows the voltage vs. currentcharacteristics of the light-emitting elements 7 and 8.

Further, FIG. 50 shows the emission spectra of the light-emittingelements 7 and 8 at a current of 1 mA. As apparent from FIG. 50, lightemission from each of the light-emitting elements 7 and 8 were from2PCAPA.

The CIE chromaticity coordinates of the light-emitting element 7 at aluminance of 3300 cd/m² were (x=0.31, y=0.62), and green light emissionwas exhibited. Further, at a luminance of 3300 cd/m², the currentefficiency of the light-emitting element 7 was 14.9 cd/A. Furthermore,at a luminance of 3300 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 7 were 4.4 V, 22.2 mA/cm², and10.6 lm/W, respectively.

The CE chromaticity coordinates of the light-emitting element 8 at aluminance of 2700 cd/m² were (x=0.29, y=0.62), and green light emissionwas exhibited. Further, at a luminance of 2700 cd/m², the currentefficiency of the light-emitting element 8 was 14.6 cd/A. Furthermore,at a luminance of 2700 cd/m², the voltage, current density, and powerefficiency of the light-emitting element 8 were 4.6 V, 18.2 mA/cm², and10.0 lm/W, respectively.

Further, FIG. 51 shows the results of continuous lighting tests in whichthe light-emitting elements 7 and 8 were continuously lit by constantcurrent driving with the initial luminance thereof set to 5000 cd/m²(the vertical axis represents normalized luminance on condition that5000 cd/m² was 100%). As can be seen from FIG. 51, the light-emittingelements 7 and 8 kept 92% and 90% of the initial luminance,respectively, after 140 hours. Therefore, it is understood that thelight-emitting elements of the present invention have a long lifetimeeven when the initial luminance was set to as high as 5000 cd/m².

Thus, by any of the anthracene derivatives of the present invention, alight-emitting element with a long lifetime can be obtained. Inparticular, by the anthracene derivative of the present inventiontogether with the functional layer for controlling transport ofelectrons, a light-emitting element with a longer lifetime can beobtained.

Example 7

In Example 7, a method of synthesizing9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA) represented by the structural formula (206),which is one of the anthracene derivatives of the present invention, isspecifically described.

[Step 1] Synthesis of9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA)

A synthesis scheme of 2CzPBPhA is illustrated in (E-1).

In a 100 mL three neck flask were put 1.7 g (30 mmol) of2-bromo-9,10-bis(2-biphenyl)anthracene, 0.86 g (3.0 mmol) of4-(9H-carbazol-9-yl)benzeneboronic acid, and 0.13 g (0.12 mmol) oftetrakis(triphenylphosphine)palladium(0), and the atmosphere in theflask was replaced with nitrogen. To this mixture were added 15 mL oftoluene and 7 mL of an aqueous sodium carbonate solution (2.0 mol/L).This mixture was deaerated by being stirred under reduced pressure. Thismixture was refluxed at 110° C. for 10 hours. Then, after the mixturewas cooled to room temperature, about 100 mL of toluene was addedthereto. This mixture was suction filtered through alumina, Florisil (aproduct of Wako Pure Chemical Industries, Ltd., Catalog No. 540-00135),and Celite (a product of Wako Pure Chemical Industries, Ltd., CatalogNo. 531-16855). The obtained filtrate was washed with water and asaturated saline solution in that order, and the organic layer was driedwith magnesium sulfate. This mixture was gravity filtered. The obtainedfiltrate was concentrated to give a solid, which was recrystallized withdichloromethane/hexane to give the object of the synthesis as 1.4 g of alight yellow powdered solid in a yield of 66%.

Then, 490 mg of the obtained light-yellow powdered solid was sublimatedand purified by train sublimation. For sublimation purificationconditions, the material was heated at 360° C. under a pressure of 200Pa with argon gas at a flow rate of 15.0 mL/min. After the sublimationpurification, 430 mg of 2CzPBPhA was recovered in a yield of 86%

By nuclear magnetic resonance (NMR) measurement, it was confirmed thatthis compound was9-{4-[9,10-bis(biphenyl-2-yl)-2-anthryl]phenyl}-9H-carbazole(abbreviation: 2CzPBPhA).

The ¹H NMR data of 2CzPBPhA are shown as follows: ¹H NMR (CDCl₃, 300MHz): δ=6.89-6.96 (m, 6H), 7.00-7.06 (m, 4H), 7.21-7.32 (m, 4H),7.37-7.45 (m, 7H), 7.54-7.74 (m, 15H), 7.85 (d, J=1.5 Hz, 1H), 8.15 (d,J=8.4 Hz, 2H). Further, FIGS. 52A and 52B show ¹H NMR charts. Note thatFIG. 52B is a chart in which the range of 6.5 to 8.5 ppm in FIG. 52A isenlarged.

Further, the decomposition temperature of 2CzPBPhA, which was obtained,was measured with a high vacuum differential type differential thermalbalance (TG-DTA2410SA, a product of Bruker AXS K.K.). The temperatureincrease rate was set to 10° C./min, and the temperature was increasedunder normal pressure. Accordingly, a reduction in weight by 5% was seenat 455° C. Thus, 2CzPBPhA was found to have high thermal stability.

Further, the glass transition point of 2CzPBPhA was measured with adifferential scanning calorimeter (DSC, a product of PerkinElmer, Inc.,Pyris 1). After the sample was heated to 350° C. at 40° C./min to bemelted, it is cooled to room temperature at 40° C./min. Then, by raisingthe temperature of the sample to 350° C. at 10° C./min, the measurementwas conducted. Accordingly, the glass transition point (Tg) and meltingpoint of 2CzPBPhA were 143° C. and 296° C., respectively. Thus, 2CzPBPhAwas found to have a high glass transition point.

Further, FIG. 53 shows an absorption spectrum of a toluene solution of2CzPBPhA, and FIG. 54 shows an emission spectrum of the toluene solutionof 2CzPBPhA. An ultraviolet-visible spectrophotometer (V-550, a productof JASCO Corporation) was used for the measurement. The measurement wasconducted with the solution put in the quartz cell. The absorptionspectrum from which the absorption spectrum obtained with only tolueneput in the quartz cell was subtracted is shown. In FIG. 53, thehorizontal axis represents wavelength (nm) and the vertical axisrepresents absorption intensity (given unit). In FIG. 54, the horizontalaxis represents wavelength (nm) and the vertical axis representsemission intensity (given unit). With the toluene solution, absorptionwas observed at around 291 nm, 340 nm, 369 nm, 389 nm, and 412 nm. Inaddition, with the toluene solution, the peak emission wavelengths were429 nm and 455 nm (excitation wavelength of 370 nm).

Further, FIG. 55 shows an absorption spectrum of a toluene solution of2CzPBPhA, and FIG. 56 shows an emission spectrum of the toluene solutionof 2CzPBPhA. An ultraviolet-visible spectrophotometer (V-550, a productof JASCO Corporation) was used for the measurement. A thin film samplewas prepared by evaporation on a quartz substrate, and the absorptionspectrum from which the absorption spectrum of quartz is subtracted isshown. In FIG. 55, the horizontal axis represents wavelength (nm) andthe vertical axis represents absorption intensity (given unit). In FIG.56, the horizontal axis represents wavelength (nm) and the vertical axisrepresents emission intensity (given unit). With the thin film,absorption was observed at around 293 nm, 344 nm, 398 nm, and 419 nm. Inaddition, with the thin film, the peak emission wavelengths were 438 nmand 463 nm (excitation wavelength of 380 nm).

Further, by measurement with a photoelectron spectrometer (AC-2, aproduct of Riken Keiki, Co., Ltd.) in the atmosphere, the ionizationpotential of the thin film of 2CzPBPhA was found to be 5.72 eV As aresult, it was understood that the HOMO level was −5.72 eV. Furthermore,with the use of the absorption spectrum data of the thin film of2CzPBPhA, the absorption edge was obtained by a Tauc plot assumingdirect transition. The absorption edge was estimated as an opticalenergy gap, whereby the energy gap was 2.82 eV. From the obtained valuesof the energy gap and HOMO level, the LUMO level was −2.90 eV.

Further, the oxidation-reduction characteristics of 2CzPBPhA weremeasured by cyclic voltammetry (CV). Note that an electrochemicalanalyzer (ALS model 600A, a product of BAS Inc.) was used for themeasurement.

For a solution used in the CV measurement, dehydrated dimethylformamide(DMF, a product of Sigma-Aldrich Inc., 99.8%, Catalog No. 22705-6) wasused as a solvent, and tetra-n-butylammonium perchlorate (n-Bu₄NClO₄, aproduct of Tokyo Chemical Industry Co., Ltd., Catalog No. T0836), whichwas a supporting electrolyte, was dissolved in the solvent such that theconcentration of tetra-n-butylammonium perchlorate was 100 mmol/L.Furthermore, 2CzPBPhA, which was the object of the measurement, wasdissolved in the solution such that the concentration of 2CzPBPhA was 2mmol/L. In addition, a platinum electrode (PTE platinum electrode, aproduct of BAS Inc.) was used as a working electrode, a platinumelectrode (Pt counter electrode for VC-3, (5 cm), a product of BAS Inc.)was used as an auxiliary electrode, and an Ag/Ag⁺ electrode (RE5reference electrode for nonaqueous solvent, a product of BAS Inc.,) wasused as a reference electrode. Note that the measurement was conductedat room temperature.

The oxidation characteristics of 2CzPBPhA were examined as follows. Ascan for changing the potential of the working electrode with respect tothe reference electrode from −0.26 V to 1.30 V and then from 1.30 V to−0.26 V was set to one cycle, and the measurement was performed for 100cycles. Further, the reduction characteristics of 2CzPBPhA were examinedas follows. A scan for changing the potential of the working electrodewith respect to the reference electrode from −0.28 V to −2.40 V and thenfrom −2.40 V to −0.28 V was set to one cycle, and the measurement wasperformed for 100 cycles. Note that the scan rate for the CV measurementwas set to 0.1 V/s.

FIG. 57 shows CV measurement results of the oxidation characteristics of2CzPBPhA. FIG. 58 shows CV measurement results of the reductioncharacteristics of 2CzPBPhA. In each of FIG. 57 and FIG. 58, thehorizontal axis represents potential (V) of the working electrode withrespect to the reference electrode, and the vertical axis represents theamount of current (μA) flowing between the working electrode and theauxiliary electrode. From FIG. 57, current exhibiting oxidation wasobserved at around 0.89 V (vs. the Ag/Ag⁺ electrode). Further, from FIG.58, current exhibiting reduction was observed at around −2.16 V (vs. theAg/Ag⁺ electrode).

Although the scan was repeated for as many as 100 cycles, significantchanges in the peak position and peak intensity of the CV curves werenot observed in each of the oxidation reactions and reduction reactions.This shows that the anthracene derivative of the present invention issignificantly stable against repetition of oxidation reactions andreduction reactions.

The present application is based on Japanese Patent Application serialNo. 2008-114057 filed with Japan Patent Office on Apr. 24, 2008, theentire contents of which are hereby incorporated by reference.

EXPLANATION OF REFERENCE

101: substrate, 102: first electrode, 103: EL layer, 104: secondelectrode, 111: hole-injecting layer, 112: hole-transporting layer, 113:light-emitting layer, 114: electron-transporting layer, 115:electron-injecting layer, 116: functional layer, 501: first electrode,502: second electrode, 511: first light-emitting unit, 512: secondlight-emitting unit, 513: charge generation layer, 601: source sidedriver circuit, 602: pixel portion, 603: gate side driver circuit, 604:sealing substrate, 605: sealing material, 607: space, 608: wiring, 609:flexible printed circuit (FPC), 610: element substrate, 611: switchingTFT, 612: current controlling TFT, 613: first electrode, 614: insulator,616: EL layer, 617: second electrode, 618: light-emitting element, 623:n-channel TFT, 624: p-channel TFT, 701: main body, 702: display portion,703: operation switch, 704: operation switch, 710: main body, 711:display portion, 712: memory portion, 713: operating portion, 714:earphone, 901: housing, 902: liquid crystal layer, 903: backlight, 904:housing, 905: driver IC, 906: terminal, 951: substrate, 952: electrode,953: insulating layer, 954: partition layer, 955: EL layer, 956:electrode, 1001: housing, 1002: housing, 1101: display portion, 1102:speaker, 1103: microphone, 1104: operation key, 1105: pointing device,1106: camera lens, 1107: external connection terminal, 1108: earphoneterminal, 1201: keyboard, 1202: external memory slot, 1203: camera lens,1204: light, 2001: housing, 2002: light source, 2101: glass substrate,2102: first electrode, 2104: second electrode, 2111: layer includingcomposite material, 2112: hole-transporting layer, 2113: light-emittinglayer, 2114: electron-transporting layer, 2115: electron-injectinglayer, 2116: functional layer, 3001: lighting apparatus, 3002:television set, 9101: housing, 9102: supporting base, 9103: displayportion, 9104: speaker portion, 9105: video input terminal, 9201: mainbody, 9202: housing, 9203: display portion, 9204: keyboard, 9205:external connection port, 9206: pointing device, 9301: main body, 9302:display portion, 9303: housing, 9304: external connection port, 9305:remote control receiving portion, 9306: image receiving portion, 9307:battery, 9308: audio input portion, 9309: operation key, 9310: eye pieceportion, 9401: main body, 9402: housing, 9403: display portion, 9404:audio input portion, 9405: audio output portion, 9406: operation key,9407: external connection port, 9408: antenna.

The invention claimed is:
 1. An anthracene derivative represented by ageneral formula (G12-1),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; Ar⁴ represents asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms; andR¹¹ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms. 2.An anthracene derivative represented by a general formula (G12-2),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; Ar³ represents asubstituted or unsubstituted arylene group having 6 to 13 carbon atoms;and R²¹ and R²² independently represent hydrogen, an alkyl group having1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having6 to 13 carbon atoms.
 3. An anthracene derivative represented by ageneral formula (G13-1),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; and R¹² to R¹⁶independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 10carbon atoms.
 4. An anthracene derivative represented by a generalformula (G13-2),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms; and R²³ to R²⁶ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms, or a substituted or unsubstitutedphenyl group.
 5. An anthracene derivative represented by a generalformula (G14-1),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; and R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.
 6. An anthracenederivative represented by a general formula (G14-2),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; and R²¹ and R²²independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms.
 7. An anthracene derivative represented by a generalformula (G15-1),

wherein: R¹¹ represents hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms; and R³¹ to R⁴⁰ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms; a substituted or unsubstituted arylgroup having 6 to 10 carbon atoms; halogen, or a haloalkyl group having1 to 4 carbon atoms.
 8. An anthracene derivative represented by ageneral formula (G15-2),

wherein: R²¹ and R²² independently represent hydrogen, an alkyl grouphaving 1 to 4 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms; and R³¹ to R⁴⁰ independently representhydrogen, an alkyl group having 1 to 4 carbon atoms; a substituted orunsubstituted aryl group having 6 to 10 carbon atoms; halogen, or ahaloalkyl group having 1 to 4 carbon atoms.
 9. An anthracene derivativerepresented by a general formula (G22-1),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; Ar⁴ represents asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms; andR¹¹ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms. 10.An anthracene derivative represented by a general formula (G23-1),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; R¹¹ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; and R¹² to R¹⁶independently represent hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 10carbon atoms.
 11. An anthracene derivative represented by a generalformula (G24-1),

wherein: Ar¹ and Ar² independently represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms; and R¹⁰ representshydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.
 12. An anthracenederivative represented by a general formula (G25-1),

wherein: R¹¹ represents hydrogen, an alkyl group having 1 to 4 carbonatoms, or a substituted or unsubstituted aryl group having 6 to 13carbon atoms; and R³¹ to R⁴⁰ independently represent hydrogen, an alkylgroup having 1 to 4 carbon atoms; a substituted or unsubstituted arylgroup having 6 to 10 carbon atoms; halogen, or a haloalkyl group having1 to 4 carbon atoms.
 13. The anthracene derivative according to any oneof claims 1 to 8, wherein Ar¹ and Ar² are substituents each having asame structure.
 14. An anthracene derivative represented by a structuralformula (101)


15. An anthracene derivative represented by a structural formula (201)


16. A light-emitting element comprising the anthracene derivativeaccording to any one of claims 1 to 8, 14 and 15 between a pair ofelectrodes.
 17. A light-emitting element comprising a light-emittinglayer between a pair of electrodes, wherein the light-emitting layercomprises the anthracene derivative according to any one of claims 1 to8, 14 and
 15. 18. A light-emitting element comprising a light-emittinglayer between a pair of electrodes, wherein the light-emitting layercomprises the anthracene derivative according to any one of claims 1 to8, 14 and 15, and wherein the anthracene derivative emits light.
 19. Alight-emitting device comprising the light-emitting element according toclaim 16 and a control circuit configured to control light emission fromthe light-emitting element.
 20. An electronic device comprising adisplay portion, wherein the display portion comprises thelight-emitting element according to claim 16 and a control circuitconfigured to control light emission from the light-emitting element.